COCONUT Handbook
COCONUT HANDBOOK
© Tetra Pak International S.A., 2016 PUBLISHER Tetra Pak South East Asia Pte Ltd Coconut Knowledge Centre 19 Gul Lane, Singapore 629414 EDITOR ShuQi Liu Q Communications Pte Ltd TEXT Chan Su Yin EDITORIAL CONSULTANTS Selvi Tanujaya Tan Swee Yng Studio Green Cube Pte Ltd PRODUCTION Image Printers Pte Ltd IBSN: 978-981-09-7362-9 All rights reserved. No portion of the Coconut Handbook may be reproduced, stored in any retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission in writing from the publisher. Printed in Singapore, 2016
Printed on recycled paper. The possibilities are endless.
CONTENTS 006 FOREWORD 007 ACKNOWLEDGEMENT
CHAPTER 1: INTRODUCTION 010 Origins of The Coconut 010 The Versatile Coconut 013 Coconut Production
CHAPTER 2: NUTRITIONAL AND HEALTH BENEFITS 016 Coconut Water 020 Coconut Milk 021 Coconut Oil
CHAPTER 3: COMPOSITION 024 Parts of The Coconut 025 Overall Composition 026 Composition of Coconut Water 030 Composition of Coconut Kernel
CHAPTER 4: PLANTATION 038 Varieties 040 Agronomic Characteristics of Coconut Production 044 Agroecology - Conditions Required For Growth
CHAPTER 5: HARVESTING AND POST-HARVEST MANAGEMENT 052 Harvesting 054 Post-Harvest Management
CHAPTER 6: COCONUT FOOD PRODUCTION 058 Coconut Water 062 Coconut Milk and Cream 064 Coconut Milk Beverages 064 Coconut Oil 068 Coconut Flour 068 Coconut Milk Powder 069 Desiccated Coconut 071 Nata De Coco
CHAPTER 7: THE CHEMISTRY OF COCONUT WATER 076 Composition of Coconut Water 077 Properties and Reactions of Coconut Water 081 Effects of Environmental Factors and Additives on Quality 083 Microbiology of Coconut Water
CHAPTER 8: THE CHEMISTRY OF COCONUT MILK AND CREAM 087 Composition of Coconut Milk 088 Properties and Reactions of Coconut Milk 092 Effects of Environmental Factors and Additives on Quality 093 Microbiology of Coconut Milk
CONTENTS CHAPTER 9: RECOMBINED COCONUT BEVERAGES
CHAPTER 11: LONG LIFE COCONUT LIQUID PRODUCTS
CHAPTER 12: CHILLED COCONUT LIQUID PRODUCTS
097 Major Components of Coconut Beverages
114 Processing Long Life Coconut Liquid Products
130 Processing Chilled Coconut Liquid Products
099 Recombination Technology
115 Sterilizing Effect on Coconut Liquid Products
135 Distributing and Packaging Chilled Coconut Liquid Products
102 Handling Coconut Beverages
CHAPTER 10: RHEOLOGY
117 Chemical and Bacteriological Changes with High Heat Treatment
104 Shearing
119 Shelf Life
105 Types of Viscosity
120 Producing Long Life Coconut Liquid Products
106 Types of Flow 109 Flow Behaviour Models
120 In-Container Sterilisation
110 Taking Viscosity Measurements
122 Ultra High Temperature (UHT) Treatment
111 Viscosity in Coconut Milk
CHAPTER 13: PACKAGING 138 Role of Packaging 138 Methods of Sterilizing Packaging Material 140 Selecting Packaging for Coconut Liquid Products 143 Aseptic Packaging 143 Packaging Systems for Coconut Liquid Products 150 Packaging Design Innovation
CHAPTER 14: QUALITY PARAMETERS AND QUALITY CONTROL METHODOLOGIES 154 Quality Control Methodologies and Suggested Quality Parameters 161 Accelerated Shelf Life
CHAPTER 15: CLEANING OF PROCESSING EQUIPMENTS 166 Coconut Food Soil Formation 168 Cleaning In Place (CIP) 174 Water Quality 175 The CIP System 176 Effluents
178 REFERENCES 183 INDEX
FOREWORD For centuries, the coconut – fruit of the coconut palm (Cocos nucifera L.) – has been a great source of versatility. Providing food, oil, milk and medicine, countries around the world have been producing coconut products for income. Today, the leading producers in the world are Indonesia, the Philippines and India. Together, these countries account for over 75% of total coconut production globally. More recently, the coconut has become a common visual of dreamy relaxation and increasingly, a symbol of health. In 2015, the global packaged coconut water market was estimated to be more than $1 billion, with the United States and Brazil leading in consumption and growth. It is also interesting to note that ready to drink (RTD) coconut milk beverages are growing in markets like China and the United States. The sales of coconut milk beverages in the United States has grown by three times over the past four years to 60 million Litres. In 2012 we established a Coconut Knowledge Centre (CKC) in Singapore. Recognizing the tremendous potential of the coconut, with the CKC we aim to become the food industry’s preferred supplier of fully integrated coconut solutions. With over 20 years of knowledge and expertise in the processing and packaging of coconut beverages, the range of solutions offered includes product development, technical and consumer knowledge, innovative packaging and processing solutions. As a part of our marketing services, CKC is also the key driver of partnerships in the food industry. We do so by tracking and sharing key categories, market developments and trends; capturing interesting product launches; identifying new products and market opportunities; as well as lead strategic planning and execution. These activities are intended to motivate and inspire our customers to grow profitable businesses. Therefore, this Handbook is the first of its kind that captures our considerable knowledge and experience about the coconut. This includes general and technical information such as quality aspects, processing and packaging, as well as the health and nutritional benefits of coconut. We hope that customers can establish a solid foundation for practical situations, and that the Coconut Handbook not only adds value but also serves as an extension to your knowledge on coconuts. Enjoy! Brought to you by the Coconut Knowledge Centre
ACKNOWLEDGEMENTS We are pleased to acknowledge, with appreciation, the external and internal reviewers, all experts in their field, for their extensive review of this handbook, the Coconut Knowledge Centre team for their dedication in compiling and ensuring the accuracy of its content and the assistance of various other individuals, who, in one way or another, contributed to the successful publication of the Coconut Handbook. EXTERNAL CONTRIBUTORS
TETRA PAK CONTRIBUTORS
Asian and Pacific Coconut Community Uron Salum Deepthi Nair Muhartoyo
Marketing Services Samit Chowdhury
Universiti Sains Malaysia (USM) Dr. Azhar Mat Esa Dr. Tan Thuan Chew Horticulture Research Institute, Department of Agriculture (Thailand) Wilaiwan Twishsri National University of Singapore Bernadette Pekerti
CoE Coconut Liew Mei Hin Lim Xiang Ru CoE Dairy Aseptic Cecilia Svensson CoE Beverages Christer Lanzingh Anders Lofgren CoE Processing Components (Homogenizers) Jenny Jonsson RheoLab Sofia Lundgren Development and Services Operations – Packaging Technologies: Food Packaging Safety and Interaction Dr. Alexander Saffert Engineering Design Arthur Filippis Aseptic Performance Support Lisawati Suhanda Communications Jaideep Gokhale Sharmilee Padhi Product Portfolio Rosario Ciancimino
CoE: Centre of Expertise
NOTES
CHAPTER 1 INTRODUCTION For hundreds of years, the coconut – fruit of the coconut palm (Cocos nucifera L.) – has been a great source of versatility. It provides food, drink, clothing and shelter, as well as income from its products.
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COCONUT HANDBOOK
INTRODUCTION ORIGINS OF THE COCONUT For hundreds of years, the coconut – fruit of the coconut palm (Cocos nucifera L.) – has been a great source of versatility. It provides food, drink, clothing and shelter, as well as income from its products. Due to its continuous production, the coconut is readily available all year round. Today, the main producers1 in the world are Indonesia, the Philippines and India. Each bunch of coconuts can contain between five to 12 nuts. The coconut is a source of food, oil, coconut water, coconut milk, and medicine. It has probably been used by humans for centuries. Today, it is a common visual of dreamy relaxation and increasingly, a symbol of health. From the Asian tropics to South America, the coconut has certainly spread around the globe by waves of sea-faring people migrating and trading across continents. Light and buoyant, the coconut itself can traverse significant distances by ocean currents. It was even reported that coconuts were collected from the seas in Norway, far away from the tropics!
THE VERSATILE COCONUT Break open a coconut and you will find a simple structured nut with many uses. From the flesh to water, shell and husk, each part of the coconut can become a useful object or source of nourishment. Since the late 1980s, the coconut’s water and flesh can be turned into ready to drink (RTD) coconut beverages and ready-to-use coconut milk and cream products. Often packed into cans and cartons, these products are also increasingly available in other forms of packaging.
1
Source: Asian & Pacific Coconut Community & Statistical Year Book 2013
CHAPTER 1 | INTRODUCTION
11
COCONUT WATER
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Did you know that over years coconut water has been perceived the as a dependable source of beverage? Celebrities from Hollywood are big fans of coconut water.
Year to date, Brazil is by far the largest market2, with Kero Coco as the country’s leading brand of packaged coconut water. In the United States, coconut water brands such as Vita Coco, Zico, Goya and O.N.E. are the current market leaders. In Europe, consumers are gaining more awareness about coconut water’s nutritional and health benefits. Across the globe, established brand owners of packaged coconut water are tapping into social media networks (Facebook, Twitter, Instagram) and digital marketing channels (YouTube videos, Amazon) to increase consumer awareness. Increasingly, pure coconut water and coconut water based fruit juices are seen as a lifestyle choice of the new generation across major media outlets.
COCONUT MILK AND CREAM A cooking ingredient found in many traditional Indian and Southeast Asian cuisines, coconut milk and cream is often packaged into cans and cartons for frequent consumption. Containing 14-25% fat, this staple is commonly enjoyed in sweet and savoury dishes, such as creamy chicken curries and smooth chendol desserts. To date, Indonesia and Thailand are one of the world’s largest exporters and consumers of coconut milk.
2
Source: Euromonitor International
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COCONUT HANDBOOK
COCONUT MILK BEVERAGE Leading the market for packaged coconut milk beverages is China. Yeshu is the country’s leading brand to date. With less than 1-2% fat content, coconut milk beverages are also fast becoming low fat contenders of soya and almond milk products in the United States and Europe. Increasingly perceived as a suitable dietary substitute for lactose intolerant consumers, brands like So Delicious, Silk, Alpro and Vitasoy are already diversifying their beverage offerings to include coconut milk. Many are also highlighting the healthy composition of coconut milk oil, which consists of medium chain triglycerides, better known as the next breakthrough treatment for dementia (Alzheimer’s disease)4. Like coconut water, established brand owners of packaged coconut milk beverages are tapping into social media networks and digital marketing channels to increase global consumer demand.
Major coconut producers globally
3
LARGEST ARE IN SOUTH & SOUTHEAST ASIA
Production of Coconuts in Whole Nuts (1000 nuts) and Copra Equivalent (MT)3
7. Mexico
1,463,735 292,455
4. Brazil
3,326,569 664,649
3 4
Source: Asian & Pacific Coconut Community Statistical Yearbook 2013 Source: Use of medium chain triglycerides for the treatment and prevention of Alzheimer’s disease and other diseases resulting from reduced neuronal metabolism II - US patent
CHAPTER 1 | INTRODUCTION
13
COCONUT PRODUCTION Several economies around the world are heavily dependent on the production of copra - the dried kernel of a coconut used to extract coconut oil. In 2013, it was estimated that the global production of coconuts was 73,811,551,000 coconuts or 2,896,709 MT in copra equivalent. Coconuts from Asia, Central and South Americas, as well as the Pacific islands make up 97.3% of the global production. Under suitable climate, rainfall and environmental conditions, coconuts can germinate and grow into coconut palms and start fruiting after three years. Commercially, coconut palms are planted in different densities per hectare of land. In general, each hectare of land can plant more dwarf coconut palms with smaller fronds than tall coconut palms. More details of coconut plantation practices are covered in Chapter 4.
8. Vietnam
1,235,450 370,635
9. Thailand
838,000 220,000
1. India
24,397,000 3,485,000
3. Philippines
15,353,000 2,710,000
5. Sri Lanka
2,513,320 480,497
6. Papau New Guinea
2. Indonesia
16,463,000 3,228,111
10. Malaysia
647,000 129,386
1,482,592 299,000
PRODUCTION OF COCONUTS IN WHOLE NUTS (1000 NUTS) AND COPRA EQUIVALENT (MT) Number of Copra coconuts Equivalent (‘000nuts) (MT)
No
Country
11
Vanuatu
493,980
98,796
12
Tanzania
427,511
85,502
13
Myanmar
425,014
87,978
14
Ghana
362,495
73,151
15
China
327,400
65,415
16 Mozambique
302,108
60,361
17
Jamaica
296,671
59,334
18
Samoa
267,000
52,920
19
Nigeria
264,999
54,007
20
Venezuela
251,377
50,477
Legend: Number of coconuts (‘000 nuts) Copra Equivalent (MT)
NOTES
CHAPTER 2
NUTRITIONAL AND HEALTH BENEFITS The coconut is a nutritious fruit. With varying compositional properties, both the coconut water and kernel are edible parts packed with beneficial nutrients.
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COCONUT HANDBOOK
NUTRITIONAL AND HEALTH BENEFITS The coconut is a nutritious fruit. With varying compositional properties, both the coconut water and kernel are edible parts packed with
Long life coconut liquid products like coconut milk based, coconut water based beverages, coconut milk or cream, are sterilized by undergoing strong heat treatment to inactivate microorganisms and heat resistant enzymes. As such, they can be stored for long periods of time at ambient temperatures without bacterial growth.
beneficial nutrients.
Drinking straight from the nut, coconut water makes a refreshing drink that rehydrates efficiently. Naturally low in sugar, it contains lesser calories than the same amount of isotonic sports drink. The sweet, energy-rich coconut kernel can be enjoyed as a snack. But more often, it is desiccated or processed into coconut oil, milk or cream for easy consumption as a staple cooking ingredient. Coconut milk is also lactose free and suitable for consumers allergic to dairy products. With a significant oil component consisting more than 45% lauric acid (C12) which is a constituent of readily metabolized medium chain triglycerides (MCTs), coconut milk is easily absorbed by the body, and is considered a good source of energy.
?
In many societies, coconut water is often used to prevent and relieve health problems such as dehydration, constipation, digestive problems, fatigue, heatstroke, boils, diarrhoea, kidney stones, urinary tract infections and even sterility.
COCONUT WATER Coconut water is a natural, fat-free drink. Low in sugars and calories, it is rich in essential electrolytes and vitamins. Dubbed the “fluid of life”, coconut water is safe for everyone to drink fresh from the nut. As the Hawaiians say, coconut water is “dew from the heavens”. With the presence of hypoglycemic and hypotension-inducing compounds such as calcium and potassium, coconut water contains potential health benefits necessary for overcoming common diseases such as diabetes and hypertension. Kinetin, the growth hormone which aids cell repair and regeneration, is also present in coconut water. More importantly, coconut water is an effective rehydration fluid, suitable for oral and intravenous consumptions.
CHAPTER 2 | NUTRITIONAL AND HEALTH BENEFITS
17
REHYDRATING THE BODY The human body contains mostly water. It constitutes a major part of our body cells. Water that is found within the cells of the body is known as intracellular fluid. About two-thirds of bodily fluid is found in the intracellular space of the cell. The rest is found in the extracellular space between cells, and the blood plasma. Playing an important role in our bodies, water cushions and lubricates the brain and joints. It transports nutrients to and carries waste away from cells. It also helps regulate our body temperature by redistributing heat from active tissues to the skin, cooling our bodies through perspiration. Quick to respond to water imbalance, the body naturally adjusts water intake and excretion through homeostatic control mechanisms. When there is insufficient water intake, our blood becomes concentrated, lips turn dry, and the hypothalamus, better known as the brain centre that controls water balance, initiates drinking behaviour. On the other hand, when there is excessive water intake, the stomach expands and stretch receptors send signals to stop drinking. However, the body’s natural mechanism causes a water lag. By the time a person feels thirsty and needs a drink, the body has already lost some of its fluid. When the body loses too much water that is not replaced in time, it suffers from dehydration. Typical symptoms of fluid loss can vary from fatigue, weakness to dizziness and loss of balance (Figure 2.1).
PERCENTAGE OF FLUID LOSS
1-2%
3-4%
Above 7%
SYMPTOMS Thirst, fatigue, weakness, vague discomfort and loss of appetite
SYMPTOMS Impaired physical performance to dry mouth, reduction in urine, flushed skin, impatience and apathy
SYMPTOMS Dizziness, spastic muscle, loss of balance, delirium, exhaustion and collapse
Figure 2.1 Typical sysptoms of fluid loss
COCONUT HANDBOOK
Typically, our bodies experience changing water levels, which requires fluid replenishment to balance dehydration and rehydration accordingly. As seen in Figure 2.2, the water level drops after the body performs a series of activities, resulting in dehydration. This requires fluid replenishment. After rehydration, water levels rise back to normal again.
On average, our bodies lose up to 2.5 litres of water a day breathing, sweating, urinating and defecating. Water is also lost when we engage in regular activities like walking, driving, studying and working. After high intensity physical exercises, the body requires even greater attention to rehydration. Otherwise, the
Normal
Water Level
18
BRF
Medium
Water
Low
Dehydration
Fluid Replenishment
Rehydration
Better Rehydration Fluid (BRF) Figure 2.2 Changes in body water levels upon dehydration or rehydration
loss of water, even in the slightest amounts, can affect our mental and physical health performances.
However, it can be challenging to achieve sufficient levels of rehydration solely by drinking plain water. Even though it quenches our thirst, it may not be an effective rehydration fluid for our bodies. As we often lead fast-paced lifestyles, our bodies may need a Better Rehydration Fluid (BRF) to rehydrate within a shorter timeframe. For example, a rapid and complete restoration of fluid balance is necessary during a marathon. Runners need to keep hydrated within seconds and not pass out running long distances. Ingestion of high volumes of water may cause a fall in plasma sodium concentration and in plasma osmolality, resulting in excessive production of urine whilst delaying the overall rehydration process. As such, our bodies require BRF to replenish fluids faster. To speed up the rehydration process, they usually contain important body electrolytes (salts that dissociate into ions) like sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, sulphate, organic acids and proteins in smaller volumes. This is why carbohydrate-electrolyte sports drinks are popular as a rehydration fluid among athletes. However, these drinks may not be an ideal BRF for ordinary consumers. Often, sports drinks contain added liquid sugar or high fructose corn syrup to provide energy for working muscles during exercise. For regular, low impact activities, these additional calories may add up for ordinary consumers.
CHAPTER 2 | NUTRITIONAL AND HEALTH BENEFITS
19
ELECTROLYTES FOR REHYDRATION Unlike plain water, the presence of natural electrolytes in BRF can help the body achieve rapid recovery of fluid loss and find its balance. This is because electrolytes attract clusters of water with the slight negative charge of the oxygen atom and the slight positive charges of hydrogen atoms in water (H2O) (Figure 2.3). To be compatible with the human body, the BRF should contain sufficient electrolytes. So that when it is ingested, urinal output will be reduced and the net water balance is regained and maintained at normal levels.
With selective and semi-
H
permeable cell membranes,
H
the movement of electrolytes
O
in and out of body cells is regulated. This helps the body maintain a state of fluid balance and rehydrate when
H
H O
H
H H
Na+
O
O
H
O
H
H H
H O
H H
H O
into the vascular system and transported to all parts of the body.
H O
K+
H
the electrolytes are absorbed from the intestinal space
O
O
-
CI H
H
H
O H
H O
H
H
Figure 2.3 Clusters of water molecules are drawn to the electrolytes.
REHYDRATING WITH COCONUT WATER Due to its ability to rehydrate the human body with its nutritional content, coconut water is also known as “Nature’s Isotonic”. Compared to other beverages, the human body can absorb coconut water’s fluid levels and electrolytes more quickly and efficiently. It is a good and natural rehydration alternative to plain water and sports drinks. Unlike most varieties of sports drinks, coconut water is low in calories, carbohydrates and sodium. In addition, it contains moderate to high levels of important electrolytes, especially potassium, magnesium and calcium. As such, it complements a high potassium and low sodium diet, reduces the overall risks of chronic diseases and lowers blood pressure levels in general. While studies have shown that there is no significant difference between rehydrating with coconut water and sports drink, these fluids are significantly better than water. More importantly, rehydrating with coconut water causes the least stomach upset.
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COCONUT HANDBOOK
HEALTH BENEFITS OF COCONUT WATER Coconut water hydrates and cools the body. Regarded as a natural stress reliever in traditional Ayurvedic medicine, coconut water is widely used to remove bodily heat, thus effectively treating pimples, boils, sun burns and hot flushes. The latter is frequently experienced by menopausal women. Coconut water is also a natural diuretic. It increases urine flow and flushes out waste products from our bodies. Due to the nutritional value of these minerals, vitamins and free amino acid L-arginine, coconut water is also perceived to be heart protective. It can help lower cholesterol levels, which reduces the chances of blood clot formation in the blood vessels.
As a digestive health booster, coconut water, when combined with spices like cinnamon, cardamom, ginger, cloves, garlic cumin, coriander and turmeric, can be used to promote better health metabolism. These combinations can also be used to treat those suffering from digestive problems. When treating diarrhoea, coconut water has been proven effective to swiftly replace lost bodily fluids. Last but not least, coconut water is rich in cytokinins, which is a group of hormones that regulate growth, development and ageing in the human body. Research suggested that consuming a rich source of cytokinins may produce an anti-ageing effect on the body. This could in turn, lead to a lower risk of developing degenerative and agerelated diseases.
COCONUT MILK When processed from the kernel, coconut milk is a staple food for many. HEALTH BENEFITS OF COCONUT MILK Through the reversal of glycogen levels, studies have shown that the coconut kernel have a potential anti-diabetic activity useful for preventing diabetes.
Often found in cooking recipes for savoury and sweet dishes across the world, coconut milk is also increasingly used as a substitute for milk by lactose intolerant consumers.
At the same time, coconut milk can possibly have other anti-diabetic activities, specifically the reversal of carbohydrate metabolizing enzymes, and the reversal of pancreatic damage by an amino acid called arginine. Another study further shows that coconut milk contains a protein which displays immunostimulatory activity. This protein has the potential to increase the levels of red and white blood cells, platelets, neutrophils, monocytes, eosinophil, B-lymphocytes, T-lymphocytes and Hb, all of which are important components in building the body’s immune system (Manisha et al., 2011).
CHAPTER 2 | NUTRITIONAL AND HEALTH BENEFITS
21
COCONUT OIL A fresh coconut (wet kernel) contains about 33% coconut oil. It contains more than 90% saturated fatty acids. While an earlier epidemiologic study suggested that consuming large amounts of coconut oil, consisting of saturated fats, can lead to high blood cholesterol, later clinical studies have otherwise shown positive outcomes about the virgin coconut oil (VCO) (Marina et al., 2009). MEDIUM CHAIN TRIACYLGLYCERIDES (MCTS) Coconut oil is rich in medium chain triacylglycerides (MCTs). The term is used to describe one form of neutral lipid, which contains fatty acid molecules with a chain length varying from six to 12 carbon atoms. Otherwise known as triglycerides, it is especially high in lauric acid, a 12-carbon saturated fatty acid which makes up to 45% of the triglycerides present in Virgin Coconut Oil (VCO). When fatty acids or triglycerides are absorbed into our bodies, they are repackaged into small bundles of fat and protein called lipoproteins. They are circulated into the bloodstream to other parts of the body. These fatty acids are then deposited into our fat cells. However, MCTs are digested and utilized differently from the long chain triglycerides (LCT). Instead of being packaged into lipoproteins, they are sent directly to the liver where majority are converted into energy and hence, less get stored as body fat. MCTs are also less dense than LCT, providing an average metabolized energy of 8.0 kcal per g, compared to 9.0 kcal per g by the latter. In addition, consuming MCTs can potentially increase thermogenesis (heat generation) in the body to a greater extent than LCT. HEALTH BENEFITS OF COCONUT OIL Contrary to popular belief about saturated fatty acids, MCTs are readily metabolized as an energy source. It is often claimed that MCTs in coconut oil can increase our bodies’ resting metabolic rate, leading to long-term fat loss. Some research has demonstrated that VCO can increase thyroid activity, which corresponds to an increased metabolic rate, helping subjects lose weight in the long run. Containing 65% MCTs, Virgin Coconut Oil (VCO) is directly transported to the liver and rapidly metabolized and thereby participates less in transporting cholesterol to other parts of the body. As such, VCO can potentially help to lower overall cholesterol levels, triglycerides, phospholipids and a variety of lipoproteins.
22
COCONUT HANDBOOK
By consuming MCT-based meals, the resting metabolic rate which metabolism is carried at rest, can increase. This is due to higher energy expenditure, which can last up to six hours after a single MCT-based meal. At the same time, ketogenesis and lipogenesis (ketone and fat formation respectively) from medium chain saturated fatty acids (MCFAs) is more energy-consuming than that of low-chain fatty acids, with most MCFAs converted to ketone bodies instead of fats.
STRONG ANTIMICROBIAL PROPERTIES MCTs like lauric acid (C12) can be effective in safeguarding human bodies against a range of bacteria, such as E-coli and bacillus subtilis. Because of these anti-microbial properties, coconut oil can be topically applied to the skin to get rid of bacteria like staphylococcus aureus, which is commonly associated with acne and pimple problems. At the same time, coconut oil can be used to moisturize the skin. Containing 45% lauric acid, some studies have shown that coconut oil can be used to kill pathogenic gram-negative bacteria with an appropriate chelator. By consuming coconut oil, it is useful in supplying monolaurin to the body, producing a source of lauric acid which meets dietary needs. The presence of lauric acid, or monolaurin, also makes coconut oil a common ingredient used in beauty products to enhance hair and skin conditions.
Furthermore, monolaurin’s antimicrobial spectrum can impede spore germination and radial growth of infection-causing fungal species. It has been reported that monolaurin can kill all members of the herpes simplex virus (HSV), which plays a role in forming atherosclerotic plaques that leads to heart disease. Fatty acids and monoglycerides from saturated fatty acids ranging from C6 to C14, which includes approximately 80% of fatty acids found in coconut oil, can also kill HSV (Manisha et al., 2011). Last but not least, MCTs in coconut oil have also been reported to also disrupts membranes of viruses and interrupt their assembly and maturation, resulting in an antiviral effect against lipid-coated viruses, such as influenza virus, pneumono virus and hepatitis C virus.
CHAPTER 3 COMPOSITION The coconut’s composition is dependent on several factors such as age and varieties. This chapter gives a description of the chemical composition of the coconut, which will form a basis for understanding chemical processes in the following chapters.
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COCONUT HANDBOOK
COMPOSITION PARTS OF THE COCONUT The coconut, scientifically known as cocos nucifera, is a fibrous drupe fruit (Figure 3.1). Usually ovoid in shape, it comes in various sizes and colour (Figure 3.2). In general, a coconut takes about 12 months to mature, weighing up to 1.2-2kg.
TESTA
EXOCARP
Thin, brown layer of seed-coat immediately covering the meat. About 0.2 mm thick
The thin outermost ‘skin’ of the drupe
MEAT (KERNEL)
MESOCARP
The white, edible endosperm. Up to 11mm thick
The fibrous husk
WATER
ENDOCARP
The liquid endosperm, a slightly turbid liquid found in the cavity of the coconut
The hard shell surrounding the meat. Up to 4mm thick
Figure 3.1 Parts of the coconut Photo courtesy of Asian and Pacific Coconut Community (APCC)
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HOW WELL DO YOU KNOW THE COCONUT? Malaysians & Indonesians KELAPA
Filipinos NIYOG
Thais MAPHRAW
Brazilians COCO
CHAPTER 3 | COMPOSITION
Aromatic Dwaft
Malayan Red Dwaft
Malayan Yellow Dwaft
Malayan Tall
Tagnanan Tall
West African Tall
25
Figure 3.2 Different varieties of coconuts1
LIFE CYCLE OF THE COCONUT
Figure 3.3 Male and female flowers within a spathe (top right), and newly formed coconuts (bottom left)1
Under ideal conditions, the coconut palm produces one leaf and one inflorescence, or better known as male and female flowers within a spathe, on a monthly basis. After the inflorescence opens and fertilization of the flowers take place, coconuts begin to form (Figure 3.3). They start to grow in size, and the cavity inside the nut differentiates itself in the second month, reaching its maximum size by the seventh month, filled with coconut water. It is also during this time that a thin and soft layer of raw kernel forms. As the nuts ripen, its hardness and quantity increases at a declining rate. The thickness of the kernel also increases, while the internal cavity reduces in size. There is also a progressive decrease in the quantity of coconut water as the nut ripens. More details on the life cycle of the coconut are covered in Chapter 4.
OVERALL COMPOSITION In general, a new bunch of coconuts forms on a monthly basis. As they grow in size over a 12 month period, the volume composition of the coconut water and the weight of the kernel undergoes major changes. After they ripen, unharvested coconuts left hanging on the trees will begin to germinate. This process depletes both the coconut water and kernel to facilitate root and shoot growth in a germinating coconut. 1
Photo courtesy of Asian and Pacific Coconut Community (APCC)
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COCONUT HANDBOOK
The coconut’s composition is dependant on several factors such as age, varieties, growing seasons (monthly or yearly variabilities), geographical locations and environmental conditions, including rainfall and temperature.
COMPOSITION OF COCONUT WATER Coconut water is the liquid endosperm found in the cavity of the nut. By the third month of fruit development, there are small quantities of coconut water. This amount increases and reaches the maximum when the nut is 7-9 months old. This is also when the coconut water tastes the sweetest, and is classified as young coconut water. Coconut water harvested from nuts between 10-13 months old is classified as mature coconut water. After the nuts ripen, the amount of coconut water declines. This is because during maturation, coconut water is used to form coconut flesh inside the fruit, a phenomenon across all of the coconut’s varieties. Coconut water comprises of 95% water, with trace amounts of carbohydrates, proteins, oils, vitamins and minerals. The chemical composition of Malayan Tall Coconuts is illustrated in Table 3.1.
Malayan Tall coconuts have
PHYSICOCHEMICAL PROPERTIES
COCONUT MATURITY STAGE (MONTHS)
the highest sugar level at
5-6
8-9
>12
6.15 °Brix (total soluble solids)
Volume of water (mL)
684
518
332
(Table 3.1). Local Thai Tall
Total soluble solids (°Brix)
5.60
6.15
4.85
coconuts known as Tap Sakae
Titratable acidity (%)
0.089
0.076
0.061
pH
4.78
5.34
5.71
Turbidity
0.031
0.337
4.051
1
have an average sugar level at 6.7 °Brix (Twishsri, 2015). For Thai Nam Hom coconuts,
SUGAR CONTENT
sugar levels can reach up to 7.6-8.0 °Brix at an age of seven
Fructose (mg/mL)
39.04
32.52
21.48
months and two weeks. It even
Glucose (mg/mL)
35.43
29.96
19.06
goes as high as 9 °Brix at an
Sucrose (mg/mL)
0.85
6.36
14.37
220.94
274.32
351.10
Sodium (mg/100mL)
7.61
5.60
36.51
Magnesium (mg/100mL)
22.03
20.87
31.65
Calcium (mg/100mL)
8.75
15.19
23.98
Iron (mg/L)
0.294
0.308
0.322
Protein (mg/mL)
0.041
0.042
0.217
Total phenolics compound2 (mg/L)
54.00
24.59
25.70
age of eight months and three
MINERALS
weeks (Petchpirun,1991).
Potassium (mg/100mL)
Table 3.1 Physicochemical properties of coconut water Titratable acidity as malic acid percentage Total phenolics content, expressed as mg GAE/L Source: Tan et al., 2014
1 2
CHAPTER 3 | COMPOSITION
CARBOHYDRATES Carbohydrates, otherwise known by the general chemical formula Cn(H2O)m, consist of monosaccharides and disaccharides (simple sugars), oligosaccharides and polysaccharides (complex carbohydrates such as starch, hemicellulose, cellulose and pectin). Coconut water consists of carbohydrates, namely sucrose, glucose and fructose. These are primary sugars which contribute to the sweetness of the coconut water. As the coconut matures, more sucrose content can be found in coconut water. The reverse is observed for fructose and glucose when the coconut matures. PROTEINS Proteins, described as giant molecules made of amino acids, are an essential part of our diet. A protein molecule usually contains one or more interlinked chains of 100-200 amino acids, where they are arranged in a specific order. When the human body consumes proteins, they are broken down into simpler compounds in the digestive system and liver. These compounds are then transported to body cells, where they are used to construct and build the body’s own protein. Active proteins, better known as enzymes, control a large majority of these chemical reactions inside our bodies. They have the ability to trigger and affect the course and speed of such chemical reactions. Surprisingly, enzymes have the ability to do this without being consumed. Therefore, they are sometimes called biocatalysts. AMINO ACIDS
Coconut water contains a small
% TOTAL PROTEIN
amount of proteins. The total
Alanine
2.41
protein content of coconut
Arginine
10.75
water increases as the coconut
Aspartic acid
matures (Table 3.1). The amino
Cystine
0.97-1.17
Glutamic acid
9.76-14.5
Histidine
1.95-2.05
Leucine
1.95-4.18
Lysine
1.95-4.57
Proline
1.21-4.12
acid composition of coconut water can be found in Table 3.2.
Phenylalanine
3.6
1.23
Serine
0.59-0.91
Tyrosine
2.83-3.00
Table 3.2 Amino acid composition of coconut water Source: Rethinam P., 2006
27
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COCONUT HANDBOOK
The two major enzymes found in coconut water are polyphenol oxidase (PPO) and peroxidase (POD). Both contributes to the colouration of coconut water to pink or brown when the reaction
Coconut water also contains a small amount of enzymes, which varies according to the coconut’s maturity. When packaging coconut water, it is important to manage these reactions so that the coconut water remains colourless, ensuring a quality product over time. In general, the measurement of enzyme content is based on their enzymatic activity. As the coconut matures, the enzymatic activity of peroxidase (POD) and polyphenol oxidase (PPO) decreases (Table 3.3).
between polyphenols and oxygen is catalyzed.
COCONUT MATURITY STAGE (MONTHS)
ENZYME ACTIVITY (U mL-1 ˚Brix-1 min-1)
5-6
8-9
>12
Peroxidase (POD)
0.052
0.117
0.129
Polyphenol oxidase (PPO)
0.543
0.160
0.056
Table 3.3 Enzyme activity of coconut at different maturity stages before thermal treatments. Source: Tan et al., 2014
VITAMINS Vitamins are organic substances occurring in very small concentrations. It consists of complex chemical compositions, and is essential to normal life processes. However, vitamins cannot be synthesized by the body. Coconut water contains water soluble vitamins. In particular, Vitamin C (ascorbic acid) and a range of Vitamin B, as shown in Table 3.4. As coconut water has no
VITAMINS
oil composition, fat soluble
Vitamin B1 (Thiamin)
0.030 mg
2.5
Vitamin B2 (Riboflavin)
0.057 mg
4
Vitamin B3 (Niacin)
0.080 mg
0.5
Helps energy production, brain function and skin health. Balances blood sugar and lowers cholesterol levels too.
<1
Helps energy production, controls fat metabolism, is essential for brain and nerves. Produces anti-stress hormones (steroids), while maintaining healthy skin and hair.
vitamins are not present in significant amounts.
Vitamin B5 (Pantothenic acid)
AMOUNT % RDA
0.043 mg
FUNCTIONS Helps energy production, brain function and digestion. Maintains healthy skin, hair, nails and eyes. Also regulates body acidity.
Vitamin B6 (Pyridoxine)
0.032 mg
2.5
Useful for protein digestion and utilization, brain function and hormone production. Helps balance sex hormones, acts as a natural antidepressant and diuretic. Helps control allergic reaction too.
Vitamin B9 (Folates)
3 μg
0.75
Helps develop the brain and nerves during pregnancy, as well as form red blood cells.
Vitamin C (Ascorbic acid)
2.4 mg
Table 3.4 Coconut water vitamin content Source: USDA National Nutrient database
4
Strengthens the immune system, makes collagen for skin, bones and joints to remain firm and strong. As an antioxidant, it detoxifies pollutants and protects humans against cancer and heart disease.
CHAPTER 3 | COMPOSITION
Coconut water contains a range of important electrolytes, primarily from minerals, potassium, calcium, and magnesium (see Table 3.1) which are required to rehydrate our bodies (see Chapter 2).
29
MINERALS Electrolytes are minerals which have an electric charge in our bodies. Many of our bodily functions are regulated by the amount of electrolytes present in the body to conduct electrical signals. These electrolytes are obtained by consuming food and drink. They are also lost through sweat and urine. ACIDITY Acidity refers to the concentration of hydrogen ions in a specific amount of liquid. This varies from one solution to another. The pH symbol is used to denote the hydrogen ion concentration. Mathematically, pH is defined as the negative logarithm to the base 10 of the hydrogen ion concentration expressed in molarity i.e. pH = -log[H+]. This results in the following scale at 25°C:
Neutral Solution
Acidic Solution
Alkaline Solution
Figure 3.3 pH of different solutions
Acidity affects the flavour of coconut water. As the coconut matures, the pH of coconut water increases in alkaline levels. It becomes less acidic and, coupled with increasing sugar levels, coconut water tastes sweeter when it is seven to nine months old. Acidity also influences the thermal processing method required to package coconut water. With a pH value ranging from 4.9-5.5, coconut water is above the benchmarked pH value of 4.6. It is therefore considered a low-acid product, suitable for the growth of microorganisms. As such it is recommended that low acid products like coconut water undergo ultra-high temperature (UHT) thermal processing for a longer shelf life. This will be covered in greater detail in Chapter 11. PHENOLIC CONTENT Phenolic content contributes to the overall complex flavour profile of coconut water. Phenolic content of coconut water decreases with maturity. When oxidised, the polyphenols can also contribute to the colouration of coconut water.
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COCONUT HANDBOOK
COMPOSITION OF COCONUT KERNEL The composition of coconut kernel is commonly measured according to the percentage of oil in the kernel which is remarkably consistent across different coconut varieties. As the coconut matures, the growth of the shell cavity is almost complete before the endosperm (kernel) enters the rapid growth stage, which begins after eight months and lasts for about three months thereafter. During this stage, the amount of coconut kernel increases up to 44% of the dehusked nut’s weight (Table 3.5).
PARTS (gm)
COCONUT MATURITY STAGE (MONTHS) 7
9
12
15
Husk
1,190.0
740.0
518.5
269.0
Shell
140.0
189.1
156.6
134.3
Meat
20.3
180.5
244.5
160.4
Water
425.0
255.0
165.0
35.0
Total
1,775.3
1,365.0
1,084.6
598.7
Table 3.5 Weight of various parts of coconut (Laguna Tall) at different stages of maturity Source: Banzon et al., 1982
RAW KERNEL OIL CONTENT When a coconut matures, the weight and meat composition changes rapidly. This is because the moisture content decreases to approximately 50% when coconuts reach 12-15 months old. On the other hand, the oil composition of a coconut increases as it advances through different stages of maturity. For comparison, a younger coconut between eight to nine months old has 18-26% oil content, whereas a mature nut can have up to 43% oil content on a wet basis. This shows that the amount of oil contained in the raw material is strongly dependent upon maturity. In the initial stages of coconut fruit growth, the oil content of the kernel only increases by a small amount. However, when the coconut is nine months old, some raw kernel is developed, which can be turned into copra or coconut milk. By then, the oil content of the kernel would have increased drastically to approximately 25-30% on wet basis (50% moisture). The remaining percentage of raw kernel consists of carbohydrates, protein, fibre and ash. As the coconut continues to mature, the oil content will further increase until it peaks at approximately 43%. Thereafter, the oil content decreases when the coconut germinates.
CHAPTER 3 | COMPOSITION
31
Table 3.6 shows that different coconuts vary in the levels of oil content at various coconut ages. OIL CONTENT/% FRESH MEAT
AGE/MONTH
AROD1
SBT2
MAWA3
6
2.74
6.24
5.74
7
9.47
8.57
12.40
8
18.45
26.62
21.60
9
25.35
32.89
28.41
10
30.56
36.65
31.29
11
30.50
38.48
38.92
12
32.87
36.81
43.30
Table 3.6 Oil content of coconut at different stages of maturity AROD: Aromatic Green Dwarf SBT: Sabah Tall 3 MAWA: Malaysia Yellow Dwarf (MYT) x West Africa Tall (WAT) Source: Au WF, 2010 1 2
In most countries, coconuts are harvested at 10-13 months old. This is when high oil content can be used to produce copra, coconut milk, cream and related food products. There are two types of wet kernel – one where the testa (brown skin) is still attached to the white kernel, and another where the testa has been peeled off. COPRA Raw kernel can be dried under the sun or using a kiln to produce dried kernel, otherwise known as copra cake. This is later processed into coconut oil. Copra cake contains 6% moisture levels, with oil content ranging from 60-65%. It also consists of 27% carbohydrates, 20% proteins, fibre and ash (Table 3.7). CONTENT (%) SAMPLE
MOISTURE
OIL
PROTEIN
CARBOHYDRATES
CRUDE FIBER
ASH
4.3
59.8
10.2
24.3
7.0
1.4
3.8
63.6
8.1
22.4
6.6
2.1
4.0
59.0
9.3
26.3
11.6
1.4
WCW
42.2
37.0
7.5
12.3
14.3
1.0
WCWK5
43.5
38.8
6.2
10.6
11.7
0.9
WCT6
32.9
34.7
7.1
24.6
17.2
0.7
WC1 CWK
2
CT3 4
Table 3.7 Proximate composition of copra and coconut kernel Source: Appaiah et al., 2014 WC: Whole copra CWK: Copra white kernel 3 CT: Copra testa
WCW: Wet coconut whole WCWK: Wet coconut white kernel 6 WCT: Wet coconut testa
1
4
2
5
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COCONUT HANDBOOK
OIL At least 55% of dried kernel consists of oils like triglycerides, free fatty acids, phospholipids and unsaponifiables. It is one of the few fruits which stores a major portion of its energy source in medium chain triglycerides (MCTs) – an important source of energy for coconuts to germinate. Originating from a plant source, coconut oil is also cholesterol-free. Triglycerides contain three free fatty acids and one alcohol called glycerol. Depending on the number of multiple bonds present in its chain, a fatty acid may be classified as saturated or unsaturated. Saturated fatty acids comprise of exclusively single bonds between all carbons in their backbone. Unsaturated fatty acids have double bonds in their backbones, known as mono (if there is only one double bond), or poly (if there are multiple double bonds). Coconut kernel contains 90% saturated fatty acids and 10% unsaturated fatty acids. These saturated fatty acids are mostly MCTs with a range of six to 12 carbon atoms in their chains. A significant proportion of these MCTs is made out of 12 carbon long lauric acid (C12) (Table 3.8).
?
CHAIN LENGTH
MCTs have also been described as healthy and supportive of an efficient metabolism, providing an immediate and sustained source of crash-free energy.
FATTY ACID %
C8:0
5.6
C10:0
5.8
C12:0
52.8
C14:0
19.2
C16:0
7.4
C18:0
1.9
C18:1
5.5
C18:2
1.0
SFA1
92.7
MUFA2
5.5
PUFA
2.0
MCFA4
64.2
3
Table 3.8 Fatty acid compositions of oils extracted from wet coconut white kernel SFA: Saturated Fatty Acids MUFA: Monounsaturated Fatty Acids 3 PUFA: Polysaturated Fatty Acids 4 MCFA: Medium-Chain Fatty Acids Source: Appaiah et al., 2014 1 2
Recent studies have shown that MCTs have many health benefits. They are metabolized differently from long-chain fatty acids. Similar to carbohydrates, they are more readily oxidized through the ß-oxidation pathway, and is therefore rapidly absorbed by the body. As a result, MCTs are also used as a supplement to enhance the fat burning process and improve the body composition of fat and lean tissue.
CHAPTER 3 | COMPOSITION
33
Oil content during coconut germination Triglycerides in the coconut kernel primarily provides energy supply for the coconut to germinate and mature. Initially, the coconut uses its limited sources of sucrose as energy. When the carbohydrate store becomes exhausted after 60-90 days of germination, the growing haustorium, roots and shoots accumulate lipids rich in lauric acid (C12). This depletes the lauric acid supply in the coconut kernel. Lauric acid is presumably used as an energy source to fuel biochemical activities for growth by generating carbon. It is important to note that such coconuts should not be used for copra or coconut milk production as the available oil content is lower when germination occurs. PROTEIN Coconut kernel contains 5-10% of proteins on a wet matter basis. Coconut kernel has a mix of essential, non-essential and conditionally essential amino acids. USDA defines essential amino acids as those that have carbon skeletons which cannot be synthesized and must therefore be supplemented in the diet. Conversely, non-essential amino acids can be synthesized from simpler precursors, often essential amino acids. There are also some conditionally essential amino acids which, under regular conditions, can be synthesized when the body feels relaxed. The classification of amino acids is shown in Table 3.9.
ESSENTIAL AMINO ACIDS
NON-ESSENTIAL AMINO ACIDS
CONDITIONAL
Histidine
Alanine
Arginine
Isoleucine
Aspartic acid
Cysteine
Leucine
Asparagine
Glutamine
Lysine
Glutamic acid
Glycine
Methionine
Serine
Proline
Phenylalanine Threonine Tryptophan Valine Table 3.9 Essential, non-essential and conditional amino acids Source: USDA National Nutrient database
Tyrosine
34
COCONUT HANDBOOK
The breakdown of amino acids in coconut meal is shown in Table 3.10 below. In particular, arginine has cardio protective benefits. CLASSIFICATION Non-essential
Essential
Conditional
AMINO ACID
MOLE (%)
Alanine
8.0
Aspartic acid
9.46
Glutamic acid
23.96
Serine
3.35
Histidine
1.74
Isoleucine
3.26
Leucine
6.04
Lysine
4.67
Methionine
0.2
Phenylalanine
3.46
Threonine
2.9
Valine
6.04
Proline
4.49
Cysteine
0.37
Arginine
13.78
Glycine
7.28
Tyrosine
1.01
Table 3.10 Amino acid in coconut meal (coconut meal = defatted coconut kernel) Source: Souci et al., 1990
CARBOHYDRATES Coconut kernel contains about 10-15% carbohydrates on a wet matter basis. This makes carbohydrates the second largest dry component in coconuts. However, carbohydrates are economically less important than coconut oil, as the kernel is mostly used to extract copra oil. The remaining dry matter is used as animal feed, and coconut flour is produced for human consumption. Soluble Carbohydrates Soluble carbohydrates comprise of monosaccharides, disaccharides, oligosaccharides (e.g. mannose, galactose, sucrose, raffinose, stachyose), and polysacharides (e.g. galactomannan). In general, soluble carbohydrates decrease with the maturity of the coconut kernel. Insoluble Carbohydrates Insoluble carbohydrates include cellulose, hemicellulose, and lignin. These carbohydrates are mostly structural components of cell walls. These insoluble carbohydrates generally increase when the kernel thickens with maturity.
CHAPTER 3 | COMPOSITION
35
VITAMINS Mature coconut kernel contains both water and oil soluble vitamins. Table 3.11 shows the vitamin contents in coconut kernel.
UNIT
AMOUNT/ 100g FRESH KERNEL
Vitamin B1 (Thiamin)
mg
0.066
Helps energy production, brain function and digestion.
Vitamin B2 (Riboflavin)
mg
0.02
Maintains healthy skin, hair, nails and eyes. Also regulates body acidity.
0.54
Helps energy production, brain function and skin health. Balances blood sugar and lowers cholesterol levels too.
VITAMINS
Vitamin B3 (Niacin)
mg
BENEFITS
Vitamin B6 (Pyvidoxine)
mg
0.054
Useful for protein digestion and utilization, brain function and hormone production. Helps balance sex hormones. Acts as a natural anti-depressant and diuretic. Helps control allergic reaction too.
Folate (DFE)
μg
26
Helps develop the brain and nerves during pregnancy, as well as form red blood cells.
3.3
Strengthens the immune system, makes collagen for skin, bones and joints to remain firm and strong. As an antioxidant, it detoxifies pollutants and protects humans against cancer and heart disease.
Vitamin C (Ascorbic acid)
mg
Vitamin E (a-tocopherol)
mg
0.24
Helps the body use oxygen, prevent blood clots, thrombosis and atherosclerosis as an antioxidant. Improves wound healing and fertility, and is good for the skin.
Vitamin K (Phylloquinone)
μg
0.2
Controls blood clotting.
Table 3.11 Vitamin content of kernel Source: USDA National Nutrient database
36
COCONUT HANDBOOK
MINERALS Coconut kernel contains 1-2% ash content on a wet matter basis. The major minerals present are potassium, calcium, magnesium, and sodium (Table 3.12).
COCONUT CULTIVAR
MINERAL CONTENT (mg/kg) K
1
Cl2
P3
Mg4
Ca5
Na6
Nam Hom (Aromatic Green Dwarf)
2280
852
222
148
86
55
Thung Kled Green Dwarf
2471
785
274
174
115
64
Patio Green Dwarf
2738
732
257
150
110
53
Maphrao Fai
1897
766
245
166
113
84
Malayan Yellow Dwarf
2487
760
225
164
110
52
Table 3.12 Level of minerals/ trace metals in coconut kernel Source: Twishsri, 2009 K:Potassium Cl: Chloride 3 P:Phosphorus
Mg: Magnesium Ca: Calcium 6 Na:Sodium
1
4
2
5
FLAVOUR COMPOUNDS Flavour compounds contribute to the overall flavour profile of coconut kernel and its derived products. It is a complex mixture of phytosterols and phenolic acids (Table 3.13).
The composition of flavour
PARAMETERS
compounds changes across
Total phytosterols (mg/100g)
different varieties and maturity
Total Phenolic Content (mg/100g)
stages, imparting characteristic flavour profiles to the different coconuts.
AMOUNT 30.66 0.2
Phenolic acids (μg/100g) Syringic acid Hydroxybenzoic acid Gallic acid Cinnamic acid Table 3.13 Flavour compounds in a white coconut kernel sample from India Source: Appaiah et al., 2014
37.3 34.7 15.9 6.9
CHAPTER 4 PLANTATION Under suitable climate, rainfall and environmental conditions, coconuts can germinate and grow into coconut palms and start fruiting after three years. This chapter is an introduction to the basics of cultivating coconut palms.
38
COCONUT HANDBOOK
Solomon Islands Tall
Rennell Islands Tall
Malaysian Tall
Hybrid
Malaysian Dwarf
Fiji Dwarf
Figure 4.1 Different varieties of coconut trees1
PLANTATION Under suitable climate, rainfall and environmental conditions, coconuts can germinate and grow into coconut palms and start fruiting after three years. This chapter is an introduction to the basics of cultivating coconut palms.
VARIETIES Coconut palms can be classified according to the size and stature of the palm, and are referred to as Talls and Dwarfs. They are also monoecious. In other words, they consist of male and female flowers on the same inflorescence (spadix) that develops within a woody spathe. Depending on the variety of the coconut trees, the male and female flowers develop at same or different times. As the coconut tree is propagated by seed, they are subjected to some variations which can be distinguished in the trees, fruits and leaves. As such, there are hundreds of vernacular names for the coconut types (Figure 4.1). TALL COCONUT PALMS Tall coconut palms are usually cross-pollinated, and are subjected to the most variations. They are classified by the location where they are grown, assuming that some uniformity in the population is developed in one location across several generations, adapting to drought, high rainfall, alkaline soil or resistance to various insects and diseases long established in the specific location. This is why they are sometimes classified as West African Tall, Malayan Tall and such.
1
Sources: http://www.newtonsapple.org.uk/the-common-coconut/
CHAPTER 4 | PLANTATION
39
Tall coconut palms have longer economic lives than Dwarf trees, typically about 60-80 years, and can live up to 100 years old under favourable conditions. They also have larger fronds than Dwarf trees, so fewer Tall coconut trees can be planted per hectare of land. Tall coconut palms are also fairly resistant to diseases and pests, except some virus diseases, and thrive under different soil conditions. After six to eight years of planting, Tall coconut palms will begin to bear fruits.
Although Tall coconut trees are usually the choice for commercial planting, Dwarf varieties can be found in
DWARF COCONUT PALMS Dwarf coconut palms are mostly self-pollinated, and have fewer variations compared to Tall varieties. They are classified by the colour of the coconut fruits produced. As the name suggests, Dwarf coconut palms are smaller in stature than Tall varieties.
The Philippines, Malaysia and Indonesia where there is greater control over soil conditions, and the smaller stature allows for higher density planting.
Dwarf coconut palms have shorter economic lives than Tall palms and only live up to 60 years old. With smaller fronds, more Dwarf coconut trees can be planted per hectare of land. Compared to Tall coconut trees, Dwarf varieties cannot adapt as well to different soil conditions, and are more susceptible to diseases, although they do show good resistance to some virus diseases. However, they begin to bear fruits earlier, after only three years of planting. At about 10 years old, they come into regular fruiting. Similar to Tall varieties, the bigger the coconuts, the lesser number of fruits found per bunch. HYBRID COCONUT PALMS Hybrids are inter-varietal crosses between two morphological forms of coconut trees. In particular, hybrids from Dwarf and Tall, Tall and Tall varieties also produce high-yielding coconut palms. In general, hybrid coconut palms are more superior in terms of quality and quantity of copra production. They also contain the greatest amount of copra per nut. As such, they are usually selected for commercial planting. The hybrid crosses between Dwarf and Tall varieties have exhibited marked hybrid vigour by having the advantages found in both palms. As such, high yielding hybrid coconut trees are resistant to environmental stress, including drought and diseases. They also bear fruits after three to four years of planting. Compared to Dwarf and Tall varieties, hybrid coconut palms have more nut yields and higher copra production (Figure 4.2). The copra and oil produced are also of better quality.
Figure 4.2 A high yielding coconut palm Photo courtesy of Asian and Pacific Coconut Community (APCC)
40
COCONUT HANDBOOK
AGRONOMIC CHARACTERISTICS OF COCONUT PRODUCTION LIFE CYCLE OF A COCONUT The agronomic characteristics of coconut production can be mapped out by the life cycle of a coconut (Figure 4.3).
Flowering And fruiting
Growth and development of coconut palm
Propagation and germination
Figure 4.3 Life cycle of a coconut
FLOWERING AND FRUITING Under favourable conditions, Tall coconut palms start flowering after planting for five years (three years for Dwarf), while the fruit fully ripens after 11-12 months. Usually, only 30-40% of the fruits are carried to full term, while most are aborted within three months of pollination. The palm produces 12-15 inflorescences (spadices) each year at fairly regular intervals. This means that, every month, a new bunch of coconuts are formed. They continue to grow on the coconut tree until they are ready for harvest, or drop from the tree for propagation and germination. However the number of female and male flowers per spadix varies, depending on the variety of the coconut tree.
CHAPTER 4 | PLANTATION
Dwarf and some Tall varieties, such as the Malayan Tall, germinate while still on the palm. Others like the West African Tall and most Pacific coconut populations can take up to eight weeks to germinate.
41
GERMINATION AND PROPAGATION Propagation is done by means of the coconut fruit, which has no dormancy and requires no specific treatment for germination. However, the speed of germination varies within and among coconut ecotypes and varieties. Generally, 90% of seed fruits will germinate. The remaining 10% is usually discarded, failing to germinate due to the pathogenic infection of the seed interior caused by the fracture of the shell, after sprouting in the first three months. During germination, the coconut haustorium, starts to develop. It is a sweet, spongy mass (cotyledon) which dissolves and absorbs the endosperm. As it develops, the haustorium depletes both the coconut water and kernel, which facilitates root and shoot growth in a germinating coconut (Figure 4.4). Under the right conditions, this germinated coconut will grow into a seedling (Figure 4.5). Scientific and technological advances now allow for in-vitro collection of the coconut embryo, which can be employed in the exchange of plant materials across countries for propagation and breeding purposes (Engelmann et al., 2011).
Figure 4.4 Germination of a mature coconut into a coconut seedling1
Propagation by seed nut Seed nut collection Seed nuts may be collected throughout the year as and when they have reached the desired maturity level. When seed nuts mature, the husk loses moisture, while the exocarp (skin) starts to turn brown. When shaken, the fruit produces a sloshing sound. This indicates that the volume of coconut water in the cavity is decreasing. After pollination, seed nuts usually take 12 months to ripen, around which time they start to fall from the trees. However, when the seed nuts are collected by picking off the ground, the identity of the female parent is difficult to establish. As such, the fruit is usually picked directly from the palm, so that the female parent can be identified for seed nut production.
Figure 4.5 Coconut seedlings being prepared for propagation and planting to grow into a coconut tree1
1
Seed nuts should be selected from a block of uniform palms producing an average of at least 1,500 nuts per ha every 45 days. This is equivalent to an annual 2.8 tons of copra per ha. Within this block, the selected mother palms should have at least 40-50 full-sized nuts, anytime of the year under ordinary farm conditions (Magat, 1999).
Figures 4.4 and 4.5 Photo courtesy of Asian and Pacific Coconut Community (APCC)
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COCONUT HANDBOOK
Seed nut storage Coconuts have no dormancy period between seed nut harvesting and germination. Therefore, it is not advisable to store fruits over extended periods of time. For varieties with cultivars that germinate early, such as Malayan Talls, immediate planting with no storage period is advisable. For varieties which are slower germinators, such as West African Talls and most Polynesian types, seed nuts may be stored for up to a month with no ill effects, as long as the coconut water in the cavity does not dry out. Alternatively, seed nuts may be picked when they are 11 months old and stored in a dry cool place for longer time periods. To hasten germination, partially or completely brown seed nuts can be stored in a ventilated or open shed for three to four weeks. Seed nut planting Coconuts do not require pre-planting treatment, so seed nuts can be planted directly. To facilitate seedling selection when there is a large quantity of seed nuts, a two-stage nursery may be used (Figure 4.6). In the first stage, the germination bed allows seed nut selection based on the speed of germination (Figure 4.7). The early germinators are usually the best performers, while the slowest germinators (about 20-30% from the total seed nuts) are discarded. Figure 4.6 A coconut nursery Photo courtesy of Asian and Pacific Coconut Community (APCC)
Figure 4.7 Coconut seedlings laid out for selection
In the second stage of the nursery, seedlings are grown to an acceptable size for out-planting. Those which display abnormal attributes are culled. Here, seed nuts are laid flat in rows, with twothirds of the nut buried in coarse soil. Upon germination, nuts are pried out, trimmed of exposed roots, and planted back in the field.
CHAPTER 4 | PLANTATION
43
Transplanting The best time to transplant seedlings is at the onset of the rainy season. Seedlings should be 8-10 months old. Eight month old transplants give a better idea of their general growth and development. Differences in vigour are best seen when the seedlings are still too young to be moved, with the majority of their leaves still succulent. Before transplanting, each hold should be applied with fertilizers mixed with soil. In addition, a small amount of organic matter like coconut husks can be placed at the bottom of the hole and covered with soil, leaving about one-third free for the seedling nut to ‘sit’. For polybagged seedlings, the polybags are first removed, then the seedling is transplanted. The hold should be covered with loose topsoil, slightly firmed at the base of the crown. The top of the nut must be about 5-8 cm below the ground level. Deep planting might suffocate the bud, while the shallow planting might cause the planting material to bend, sway or lean during heavy rains and windy days. A slight depression towards the base of the crown must be provided to trap rainwater (Santos et al., 1995). Propagation by coconut embryo culture For propagation by coconut embryo culture, two coconut embryos in vitro collecting protocols have been established. One consists of storing the disinfected embryos, while the other includes in vitro inoculation of the embryos in the field. In the former, a cylinder of solid endosperm containing the embryo is removed and stored in a potassium chloride solution for transporting to a laboratory, where the cylinders are disinfected again and the embryos extracted. These are placed in a solid embryo culture medium in a culture tube, and inoculated in vitro under sterile conditions. In the latter, in vitro inoculation of the embryos in the field follow steps similar to storing disinfected embryos. However, instead of being stored in potassium chloride solution, the cylinder of endosperm is directly placed in a Petri dish. The embryo is extracted on the field inside a wooden box, which provides some protection from external contaminants. Then, it is rinsed again and inoculated to a solid embryo culture medium. Next, the tube is transported to a laboratory where the embryo is allowed to grow on the culture medium.
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When the first true leaf is visible and the root system starts developing at least one root with ramifications, the plantlets are transferred to light conditions. Thereafter, plantlets are transferred to large tubes containing fresh medium every 4-6 weeks. When plantlets display 3-4 unfolded green leaves, they can go on to acclimatisation after 6-7 months of initial inoculation. At this stage, plantlets are removed from culture tubes and planted in the greenhouse where soil nutrition and quality are controlled. After two months, they are then transferred to plastic bags filled with forest leaf mould mixed with sand before they are planted in the field. GROWTH AND DEVELOPMENT OF COCONUT PALM The most rapid growth occurs between the second and fifth year of planting a coconut palm. A stem appears under the crown after growing for 3-4 years, and stem elongation reaches 30-50 cm annually, but slows down in older palms which are 40 years and older. After the sixth year, fruit production increases at the expense of vegetative growth. Thereafter, the coconut tree experiences fairly constant growth as yields are sustained over the next 40 years, and palm age can be roughly gauged from the length of the stem.
AGROECOLOGY - CONDITIONS REQUIRED FOR GROWTH SOIL Coconut prefers fertile and adequately drained soils with a minimum depth of 75 cm, with high water-holding capacity (at least 30% clay content). A wide range of soil textures (sand-clay) is suitable for coconut production. The palm tolerates soil pH from 5.0-8.0. For optimum growth, a pH range of 5.5-6.5 is ideal (Magat, 1999). RAINFALL As one of the thirstiest denizens of the plant kingdom, water plays an indispensable role in the successful cultivation of coconut palms. As such, it is strongly advised that coconuts be planted at the start of the rainy season, or under weather conditions with a rainfall of 1500-2300 mm evenly distributed throughout the year. For profitable cultivation, total rainfall of 1800-2000 mm or more per year or 150 mm per month (4-5 mm per day), evenly distributed throughout the year is ideal (Magat, 1999). However, coconuts can still grow normally even with less rainfall, provided there is enough soil moisture or a high water table with good drainage. This is because the coconut palm requires large quantities of water to grow well, and water constitutes about 50% the total weight of fresh coconuts.
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45
Generally, the coconut palm absorbs 24 litres of water each day, and the daily loss of moisture from mature coconut palm varies from 28-74 litres per day. However, the coconut does not like being waterlogged, and coconut palms will not survive more than two weeks of surface water logging. RELATIVE HUMIDITY For normal growth and high yield, the relative humidity should be 80-90% and must not go below 60%. A persistently high humid condition is not suitable for the palm as it favors the rapid spread of Phytophthora disease (fruit rot or bud rot), a fatal disease commonly observed in yellow, red or orange dwarf varieties (Magat, 1999). LATITUDES, ALTITUDES AND SALT The coconut thrives in the tropics between latitudes 23°N and 23°S, at low altitudes not exceeding 600 m, where the temperature is between 22-34°C, with a mean temperature of 28°C. Ideally, the relative humidity for coconuts to thrive should be more than 60%. There should also be no prolonged soil water deficit and excessive soil salinity. As coconuts are semi halophyte, they can grow in solutions where roots come into constant contact with salt concentrations of up to 0.6%. Therefore, it is possible to temporarily use sea water for irrigation purposes without any ill effects. However, an exclusive use of sea water is detrimental to the growth of coconuts, especially young trees. FERTILIZERS Salt fertilizer can also be applied to improve yields. In addition, they are environmentally-friendly.
Salt fertilizers accelerate crop growth and development, increase copra weight and the number of nuts per tree, as well as minimise leaf spot damage.
The use of sodium chloride (NaCl) or common salt as fertilizer is a practical mean of increasing coconut production. Salt is the cheapest and best source of chlorine to increase copra weight per nut and copra yield per tree. Generally, bearing palms are fertilized annually in areas with almost uniform rainfall distribution. In areas with distinct wet and dry seasons, uneven rainfall distribution, and those with sandy soils, fertilizers are best applied every six months. In a longterm study of salt application, 1.5 kg NaCl/tree per year is considered to be most effective and economical to increase copra weight/nut and copra yield (per tree and per hectare). Split application is done at the pre-bearing stages of palms, equivalent to 1-4 years. This practice helps reduce the loss of fertilizer nutrients through leaching and runoff, which makes the use of fertilizer more effective (Magat, 1999).
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The use of multi-nutrient fertilizers (MNF), such as NitrogenPhosphorous-Potassium (NPK)-Sulphur-Sodium-Chlorine-Boron, is even more effective. This can increase yield by another 20%, 33% and 66% above that of salt-fertilised palms in the first, second and third years respectively (PCA, 2010). More importantly, the use of MNF can help to prevent mineral deficiency, which can lead to retarded root growth, delayed flowering, ripening of nuts and poor leaf health. In turn, these may result in smaller fruits produced and lower overall yield. PLANTING SYSTEMS Monocrop or pure palms are planted at a density that allows the tips of horizontally held mature leaves to touch. The planting density is about 7-8 m spacing for Dwarf palms, 8-8.5 m for hybrids and 9-10 m for Tall palms. This is because the crown size of Tall palms are approximately 30% larger than hybrid and Dwarf varieties. This results in about 115-236 palms/ha under triangle system, or 100-200 palms/ha under square system. Considering the same distance of planting, the triangular system can accommodate 15% more palms than the square system. As a guide, Table 4.1 shows the population and planting density under typical square and triangular systems of planting (Magat, 1999).
SPACING
POPULATION DENSITY (palms/ha) SQUARE METHOD
TRIANGULAR METHOD
8mx8m
156
180
8.5 m x 8.5 m
138
160
9mx9m
134
143
10 m x 10 m
100
115
Table 4.1 Square and Triangular Systems and Their Planting Densities
YIELDS Yields vary from place to place. In general, commercial monocrop plantings out yield those in home gardens. Higher yields are obtained when there are more inputs, such as proper management, maintenance and regular fertilization. Annual yields range from 15-20 kg of copra or, depending on the fruit size, 50-80 fruits per coconut palm.
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COMPETITION Coconut competes well with most plants for nutrients and water. However, its growth and yield slows in the presence of aggressive grasses such as the Imperata cylindrical. Pasture grasses, including Ischaemum aristatum, are commonly grown under old palms for cattle grazing. In general, coconuts grow poorly in shade. For instance, seedlings planted under older palms or other trees can take up to 10 years to flower with low yields. For maximum productivity, all weeds that compete with coconut for nutrients, water, or sunlight should be suppressed. However, keeping the soil bare is not always a good management practice because apart from being laborious, it increases erosion risks and nutrient loss, and causes humas. Therefore, weeding may be done manually or mechanically. Animals can also be allowed to feed on them. However, it is better to leave about 1.0-1.5 m around the base of the palms uncropped. In addition, to minimise soil water loss during dry season and the growth of weeds, mulching with two layers of coconut husks around the base of coconuts can be done (Magat, 1999). PESTS AND DISEASES Coconut yield is susceptible to various pests and diseases, which affects the quality of coconut production during their life span. They even cause the palm to die. Common examples are as follow: Rhinoceros beetle, Orycts rhinoceros Rhinoceros beetle (Figure 4.8 and 4.9) attacks coconut palms in all stages of growth especially young palms which can be killed. Its entry hole is marked by chewed up tissues; feeding of the beetle is shown by bilaterally symmetrical triangular cuts on the youngest open frond.
Figure 4.8 Rhinoceros beetle
1
Figures 4.8 and 4.9 Photo courtesy of Asian and Pacific Coconut Community (APCC)
Figure 4.9 Rhinoceros beetle infected coconut palms
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Nematode (worm), Radopholus similis The burrowing nematode (worm), attacks the coconut root zone. Symptoms include main roots showing lesions and rotting as the nematode penetrates delicate regions behind the root cap. Eriophyid Mites, Aceria guerreronis Keifer Eriophyid Mites are so minute in size that they are not visible to the naked eye. Measuring 200-250 microns in length and 20-30 microns in width, they remain underneath the periyanth (cap) of the coconut and injures by feeding on the soft paranchymatic tissues. Visible symptoms are brown discolouration in patches of the husk. In severe attacks of the button sheds, setting percentage of coconut is very poor. Coconuts are deformed and undersized, with poorly developed kernel and husk. Red palm weevil, Rhynchophorus ferrugineus The larvae of the Red palm weevil (Figure 4.10) can tunnel into the trunk of coconut palms, destroying the entire cabbage at which time the young fronds wilt. This can eventually cause palms to die. Infestation occurs when there are chewed fibres and reddish-brown sap oozing from entrance channel.
Figure 4.10 Red palm weevil
Coconut scale, Aspidiotus destructor Signoret Coconut scale (Figure 4.11) attacks palms at all stages. Infested leaflets turn yellowish, due to numerous spots which mark the position of scales on the underside of leaflets. This reduces the vitality of young palms. As a result, there is low yield.
Figure 4.11 Coconut scale infected coconuts
1
Figures 4.10-4.12 Photo courtesy of Asian and Pacific Coconut Community (APCC)
CHAPTER 4 | PLANTATION
DISEASES
Basal stem rot is a type of fungal disease which affects coconut production. The causal agent for basal stem rot is Ganoderma boninense. The symptoms are similar to severe drought, making it difficult to recognise under drought conditions. These include few, poorly developed female flowers; narrow and elongated nuts in the immature stage; small and distorted nuts in mature stage; thicker husks; dark brown streaks on the husk, and premature nut fall. At later stages, reddish brown discolouration develops at the base of the stem, accompanied by exudation of brown, viscous gummy substance. Dry rot of internal tissue also occurs at the base of the stem, leading to the formation of large cavities in the bole, causing palms to break off from the base and fall. Stem bleeding is associated by fungi - Thielaviopsis paradoxa, Phytophthora palmivora and P. katsurae. Symptoms include bleeding patches leading to a reddish, brown liquid oozing out of the stem. When old lesions stop oozing, the fluid dries and turns black. The tissues under the lesions rot, turn yellow to black, and disintegrate to a dry powdery mass. Bud or heart rot commonly occurs in humid regions through fungal infection. Symptoms include the withering of the youngest unfolded leaf and progressive leave fall, starting with the youngest. Light brown speckles are also found on the petiole bases of the youngest leaves. Often, the first typical external symptom is the withering and tilting of spear, at the advanced stage of the disease. Lethal yellowing disease, associated with phytoplasma, causes coconuts to drop prematurely. New inflorescences will also blacken. The first affected inflorescences usually show partial necrosis but as the disease progresses, newer inflorescences show more extensive necrosis. Most of the male flowers die and no fruit are set on those affected inflorescences. Leaves usually start to yellow after necrosis has developed in more than two inflorescences. The first leaves to turn yellow are the old, lower hanging ones. Yellowing then advances upwards, affecting the younger middle and finally, the young, upper leaves. When yellow leaves turn brown, they desiccate and die while hanging for a few days before falling. Eventually, the whole crown perishes, leaving a bare trunk or ‘telephone pole’. Bogia Coconut Syndrome (Papua New Guinea) exhibits symptoms similar to the lethal yellowing disease. Symptoms include leaflet yellowing, necrosis, frond collapse, premature nut fall and subsequent death. The Weligama Wilt disease is caused by a phytoplasma. It is characterized by the debilitating nature of palms. Symptoms include leaf flaccidity, yellowing and finally succumbing to an infection with other fungal diseases like leaf rot. Occurring in Sri Lanka, the disease is transmitted by insect vectors which are multi-host species. Root wilt disease (RWD) is caused by phytoplasma. It exhibits major symptoms like leaves wilting, drooping and flaccidity; as well as ribbing, yellowing and necrosis of leaflets. These are typical of foliar diseases. Cadang-cadang is a common viroid disease affecting coconut plantation in the Philippines. The symptoms include the production of rounded nuts with equatorial scarifications, as well as smaller, occasionally distorted nuts. As a result, nut production ends after four years or less. Spots are also found on the lamina of the third or fourth leaf below the spear. The bacterial leaf stripe disease gives coconut palm the symptoms of a pale, yellowish streak on the outer edges of both the leaf blades which develops into stripes. If virulent, the disease can infect the whole tree in five days with abundant bacterial ooze on the under surface of leaflets.
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METHODS COMMONLY USED TO PREVENT AND TREAT PESTS AND DISEASES
Chemical sprays to reduce the severity of attack
Mechanical methods, such as light traps, to capture pests
Quarantine regulations introduced for all plant materials
Biocontrol agents like parasites and parasitoid under controlled conditions
Natural predators are introduced into the plantation grounds
Removal of plant materials which provide a habitat and breeding ground for pests in the plantation
Figure 4.12 Methods commonly used to prevent and treat pests and diseases
CHAPTER 5
HARVESTING AND POST-HARVEST MANAGEMENT Coconut palms are productive throughout the year. However, the yield may vary from season to season. Almost on a monthly basis, a normal bearing coconut palm usually produces one harvestable bunch.
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COCONUT HANDBOOK
HARVESTING AND POST-HARVEST MANAGEMENT Coconuts are harvested for
HARVESTING
different consumptions. For
Coconut palms are productive throughout the year. However, the yield may vary from season to season. Almost on a monthly basis, a normal bearing coconut palm usually produces one harvestable bunch. On an annual basis, the number of bunches harvested per palm reaches about 14 from Tall varieties and 16 from Dwarf trees.
the sweetest and tastiest coconut water, seed nuts usually take seven to nine months to grow from the flower opening before it matures. For copra, coconut milk and other derived food products, seed nuts take 1013 months to mature from
However, due to practical economic reasons, harvesting for copra production usually takes place every 45-90 days. Instead of harvesting on a monthly basis, this allows them to collect a few bunches, ranging from 10-13 months old, all at one go.
the flower opening, so that the kernel is thick enough for commercial use.
FREQUENCY AND AMOUNT A bunch of coconuts from each tree has five to 15 nuts. It can be harvested every month from a coconut palm. To economise, farmers usually yield two to three bunches from each tree. This occurs every harvest cycle, which ranges between 45-60, or 75-90 days. On average, 10-45 nuts can be collected from each coconut tree at various maturity stages every harvest cycle. In order to yield a good number of mature nuts with high copra and oil recovery, the Asian and Pacific Coconut Community (APCC) recommends that each harvest takes place in 45-day harvest cycles. METHODS The methods of harvesting coconuts vary from country to country, sometimes even among provinces within the same country. Nevertheless, the two most common methods of harvesting coconuts are the pole and climbing methods. In some countries like Thailand, Malaysia and Indonesia, coconuts are also harvested by trained monkeys. In others like Papua New Guinea, the coconuts are left to fall to the ground and collected thereafter.
Figure 5.1 Harvesting with a pole
For the pole method, farmers use a harvesting scythe at the end of a long bamboo pole to cut the coconut bunch, which is left to drop from the palm. The advantage of this method is that it is generally faster, more efficient, less tedious and dangerous compared to the climbing method. This way, the harvester can harvest more nuts per unit time from a larger number of trees. In some coconut plantations, drains are dug out in between the rows of coconut palms, so the coconuts drop into the body of water which cushions the falling impact.
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Using the climbing method (Figure 5.2 and 5.3), the farmer, worker or trained monkey is engaged to climb up the coconut tree, with or without a climbing device. For easy climbing, some coconut trees have grooves carved into their sides. Although this is dangerous, it is very commonly done to harvest coconuts. Palm climbing devices, like the ones adopted in India in Figures 5.4 and 5.5, lowers the danger imposed on the harvesters.
Figure 5.2 Harvesting by climbing
Figure 5.3 Harvesting by trained monkey where labour are scarce
Figure 5.4 Palm climbing device1
Figure 5.5 Harvesting by climbing with Palm climbing device1
The advantage of climbing is that the harvester can clean and inspect the crown of the palm for pest and disease attacks. However, the grooves which are carved to construct steps in the coconut trunk make the coconut trees less suitable for timber purposes. These fractures could also be potential entry sites for pests.
1
Figures 5.4 and 5.5 Photo courtesy of Asian and Pacific Coconut Community (APCC)
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POST-HARVEST MANAGEMENT YOUNG COCONUTS Bunches of young coconuts are harvested for coconut water. They are transported as whole coconuts to the processing site, where each coconut is cut from bunches in a process called de-fruiting. Trimming Trimming decreases the weight of the coconuts, resulting in substantial savings in transportation. It takes most of the husks away, so it is easier for consumers to drink water straight from the coconut. If coconuts are meant for the local market, they are distributed among the sellers in bunches or individual fruits. If the coconuts are meant for the export market, the husks are first trimmed with sharp knives. They are then trimmed again into different cut styles as seen in Figure 5.6.
Trimmed coconut with all green exocarp removal
Part of exocarp is cut; trimmed into tapered-cylindrical form with cone cover-top
Part of exocarp is cut; top is trimmed into cone-cover shape
Polished coconut with cone cover stem end
Figure 5.6 Some trimming styles of young coconuts
Packing and pre-cooling After trimming, the coconuts are dipped into 1-2% sodium metabisulphite solution for up to three minutes. This prevents browning and mould infection of the white husks. It can be partially substituted by using oxalic acid or a blanching process to minimize mould formation. Thereafter, young coconuts are individually packed in polypropylene or HDPE bags and then repackaged into boxes for easy transportation. These boxes are then pre-cooled to less than 4°C and stored in refrigerated conditions before transportation. Transportation The trimmed young coconuts are transported chilled via sea or land, and the cold chain is kept constant throughout. They are then sold in the refrigerated segments of retail channels, such as supermarkets, cafés and restaurants.
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MATURE COCONUTS After 10-13 months, mature nuts are harvested for coconut milk and other coconut derived food products. Usually, they are gathered together on a single layer on the ground. Some farmers practise seasoning, in which the coconuts are placed on dry ground and left to mature for another three weeks to a month, so that it is easier to dehusk, deshell and pare the testa (skin) off from the seasoned coconuts. They are also placed on dry ground as coconuts tend to germinate under damp conditions. Dehusking Coconuts are first dehusked before being transported by trucks, carts or boats to the processing site. Otherwise, they can be bulky. Dehusking can be done manually or by semi-automated procedures, but the former is more commonly used.
Figure 5.7 Mechanical coconut dehuskers Photo courtesy of Asian and Pacific Coconut Community
In manual dehusking, a sharp-pointed shard of steel is used. It is positioned vertically with the point up and the broader part firmly placed on the ground. The worker is trained to impale the coconut on the sharp point with a strong, determined downward movement. A few impaling strokes loosen the husk, which comes off in one or a few pieces. As this is a dangerous method of dehusking, some mechanical coconut dehuskers have been developed which are capable of dehusking 300-1200 coconuts per hour (Figure 5.7). Deshelling and paring Dehusked coconuts are then transported to processing sites to remove their shell and optionally, the skin. Next, they are further processed into coconut milk, cream or other coconut derived food products like desiccated coconut.
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Copra
For coconuts which are specifically used for copra, they have to undergo a seasoning stage in order to increase copra recovery and quality.
Ripening for copra processing For copra, it is recommended that the harvested nuts undergo a further ripening stage on dry ground for a month. This promotes desirable changes in the greener or somewhat less mature nuts, which is said to improve the quality of the coconut kernel, thereby reducing the tendency to produce rubbery copra, making dehusking a much easier process. Kernel drying for copra processing After seasoning, the coconuts are dehusked and split so the coconut water is thrown away and lost to the soil. Alternative uses for coconut water like biogas generation, or processing and packaging for readyto-drink purposes, can also help to reduce pollution. The coconut kernel is then dried under the sun or in a kiln, hot air dryer. This improves oil yield and reduces aflatoxin incidence. Harmful to humans and animals, aflatoxin occurs when mould, such as Aspergillus flavus, grows on improperly dried copra. Drying the kernel reduces the moisture content from 50% down to 6%, resulting in copra. It is then sent to the processing site for oil extraction.
CHAPTER 6
COCONUT FOOD PRODUCTION It is popular among Indonesians to say that there is a use for the coconut palm in every day of the year. Indeed, coconuts can be processed into many products. The coconut kernel and water are two edible parts which form the basic ingredient for a variety of coconut products.
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COCONUT FOOD PRODUCTION It is popular among Indonesians to say that there is a use for the coconut palm in every day of the year. Indeed, coconuts can be processed into many products. The coconut kernel and water are two edible parts which form the basic ingredient for a variety of coconut products. Figure 6.1 in the next page shows how these products are made through a combination of processes and sometimes, a byproduct of each other.
COCONUT WATER Coconut water is a refreshing and cooling drink. Its sodium and potassium content makes it an ideal drink for rehydration. In a healthy, undamaged coconut, the water is even sterile. During World War II, coconut water was used intravenously to treat patients suffering from blood loss when blood plasma was not available. It is also a ready source of clean drinking water, especially after a natural disaster. There was little need to develop scientific knowledge on coconut water processing as it was typically consumed fresh from the nut. The science behind coconut water and its characteristics was only required when there was exponential demand from various markets which did not produce enough coconuts. As such, coconut water was extracted, processed, packaged and transported across long distances. This presented new challenges as coconut water reacts quickly once the nut is opened. With the advances in aseptic packaging technology, the shelf life of coconut water can be extended for up to a year. Please refer to Chapter 11 for more details. Coconut water is harvested from young and mature coconuts. Due to different characteristics of the husk, shell and interior of the coconut, the extraction methods for both types are slightly different. Nevertheless, both types of coconut water can be extracted and processed for packaging. They are drilled into the cavity to obtain the coconut water. Normally, the drilling of a hole occurs at or near one of the three eyes of the coconuts where the shell and flesh is the thinnest or weakest.
CHAPTER 6 | COCONUT FOOD PRODUCTION
PRODUCTION OF COCONUT FOODS
1st Trim
Young Coconut
Transport to processing site
Coconuts in bunches
2nd Trim
Shrink wrap & box
Dip in SMB
Coconuts for local/export market
Store at 4 oC
Defruit & quality check: - Size, Weight - Cracks in husk - Foul Smell Manual Cutting Coconut Water
Wash
Nata de coco
Ferment
Automated cutting
Nata de coco
Ferment
Coconut Water
Concentrate
Coconut Water Concentrate
Coconut Beverage
Deshell
Drill
Spray Dry Mature Coconut
Dehusk
Quality check: - Size - Cracks in husk, teary eyes, bloated eyes
Skim Coconut Milk
Coconut Milk/Cream
Deshell
Season
Halve
Brown Skin Kernel
Cut, Grind & Press
Fresh-wet extraction
Virgin Coconut Oil (VCO)
Pare
Dehusk
Halve
Coconut water as waste
Dry
Copra
Low Fat Desiccated Coconut (from white meat residue)
White Meat Kernel
Animal Feed
White/Brown meat residue
Grate & Dry
Dry Extraction
Crude Coconut Oil
Refine, Bleach & Deodorize
RBD Coconut Oil
Dry
White/Brown meat residue Desiccated Coconut
Coconut Milk Powder (full fat)
Fresh-dry extraction
Animal Feed (from brown meat residue)
Virgin Coconut Oil (VCO)
Legend: Raw materials from young coconut Raw materials from mature coconut Production stages Products Waste/by-products Further Mixing and Processing
Figure 1 Integrated Processing of Coconut Products (Flowchart)
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Coconut water is also considered a by-product of desiccated coconut or coconut milk production, where the mature coconuts are collected and halved. As consumers increasingly demand the best quality coconut water, manufacturers prefer to drill the mature coconuts instead. This drains the coconut water out by minimizing the contamination of coconut water from the loose soil and fibres from the mature coconut shell. After extraction, coconut water is filtered. Filtration can be done using a cheese cloth, fine filter or a scrap surface filter. This is especially important for mature coconut water, as dry husk fibres and dirt from the shell of mature nuts can easily get into the coconut water during extraction. After filtration, the coconut water is quickly cooled to retard any deterioration reactions. Then, it is sent for deoiling (separation), subsequent pasteurization and aseptic packaging. If coconut water is extracted at a location away from the aseptic packaging site, the filtered coconut water can be packed into food grade plastic bags, quickly cooled and transported to downstream processing. Please refer to Chapters 7, 11 and 12 for more details. Often, it is not commercially viable to transport large amounts of single strength coconut water (92-95% water content) in bulk to markets where coconuts are not readily available. As such, technological advances can concentrate coconut water to higher soluble solid levels of 60-65 °Brix (or 35-40% water content), saving considerable resources on transportation. To produce coconut water concentrate, fresh coconut water is first passed through a pre-concentration stage of reverse osmosis to increase the total solids. Then, it goes into a multiple effect evaporation stage to increase °Brix levels. Usually, the product is concentrated to 60-65 °Brix and packed into 200 kg plastic bags in drums for bulk transportation under ambient conditions. At this high °Brix level, the concentration of coconut water is somewhat selfpreserving. Upon arrival, it is recommended that the concentrate be stored at -18°C for use up to two years. To reconstitute the coconut water concentrate to single strength coconut water for further aseptic processing and packaging, concentrate is blended with water at appropriate proportions to get the desired °Brix level.
CHAPTER 6 | COCONUT FOOD PRODUCTION
Coconut water is a good rehydration drink that is cholesterol free, low in fat, and high in electrolytes. It provides an alternative to carbohydrate based sports drink, providing the same rehydration benefits with lower calorie count. Coconut water is also used as a base for coconut-flavoured beverages. Usually, taste can be further enhanced and diversified by adding other ingredients such as fruit juice, tea, coffee, chocolate and more. Besides drinking, coconut water can also be used for cooking. For example, it is commonly used to cook rice and other grains, braise meats like pork and beef, make clear soups and salad dressings.
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COCONUT MILK AND CREAM When the kernel is hard and thick, it is full of carbohydrates, oil (mainly medium chain triglycerides, MCTs) and aromatic compounds. This is suitable for coconut milk extraction, imparting a unique flavour profile and creamy texture to coconut milk and cream.
Coconut milk and cream is produced from 10-13 months old mature coconuts when the kernel is hard and thick. They are natural oil-in-water emulsions extracted from the mature coconut kernel. The difference between coconut milk and cream is the amount of fat in the products. It is important to categorize coconut milk products according to fat content. The Codex Standards for Aqueous coconut products states that coconut milk should contain at least 10% fat, 2.7% non-fat solids, and 12.7-25.3% total solids. While coconut cream should contain at least 20% fat, 5.4% non-fat solids and 25.4-37.3% fat (Table 6.1). TOTAL SOLIDS (%m/m)
NON-FAT SOLIDS (%m/m)
FAT (%m/m)
MOISTURE (%m/m)
pH
MIN. - MAX.
MIN.
MIN.
MAX.
MIN.
Light coconut milk
6.6-12.6
1.6
5
93.4
5.9
Coconut milk
12.7-25.3
2.7
10
87.3
5.9
Coconut cream
25.4-37.3
5.4
20
74.6
5.9
Coconut cream concentrate
37.4 min.
8.4
29
62.6
5.9
PRODUCT
Table 6.1 Classification of coconut milk and cream Source: CODEX STAN 240-2003
To extract coconut milk and cream, mature coconuts must first be dehusked and deshelled. The layer of brown skin is also pared off to get a layer of white kernel, as the skin can impart a brown colour and slightly bitter taste to extracted coconut milk. The kernel is then washed, drained and grated by machine into kernel flakes. Thereafter, it is mechanically pressed to extract the coconut milk.
? The fat and oil levels in coconut milk and cream is dependent on the amount of water added during the extraction process. As more water is added, fat levels are lowered in the resulting product.
To extract coconut milk at home, consumers usually buy grated kernel and mix with water, as water is especially helpful in manual extraction. The mixture is then poured into a sieve or a muslin cloth where it is squeezed by hand. This extraction can be repeated a few times by adding water to maximize the soluble material extracted from the kernel. With each subsequent extraction, the oil level of the resulting coconut milk decreases, which varies according to the amount of water added to the mixture. Extracted coconut milk can either be used immediately, or left to stand. Upon standing, it separates into two distinct layers – the oil-rich phase (cream) on top, and the waterrich (“whey”) below.
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To extract coconut milk for industrial manufacturing purposes, mature coconuts go through deshelling and paring. Pieces of kernels are then sent into industrial scale cutters and grinders. In integrated plants, the by-product coconut water is also collected by drilling the coconut before deshelling, or halving the coconuts after deshelling. Next, grated coconut kernel then goes into a series of screw presses to extract coconut milk. The residual kernel from this first press is then mixed with water before it is pressed again to increase extraction yield. Extraction yield can be represented by oil recovery yield.
Used widely in South and Southeast Asia, coconut milk lends a creamy texture and coconut flavoured aroma to
WHERE: Oil Amount of oil extracted X•Y = Recovery = Amount of oil in feed w•c yield
various cuisines. In Bahasa, this is commonly referred to
X = amount of coconut cream Y = fat content (%) in coconut cream w = average weight of kernel c = fat content (%) in kernel
as “lemak”. In general, the fat levels in packaged coconut milk and cream ranges from 17-25% in ASEAN countries.
After extraction, coconut milk is filtered to remove large contaminants. It can then be standardized to a pre-determined level of fat and blended with other ingredients. Finally, coconut milk is pasteurized and aseptically filled into packages for transportation to global markets. The composition of coconut milk can be found in Table 6.2. PHYSICAL PROPERTIES
The composition of coconut
RANGE
milk is dependent on factors
Specific gravity
1.0029-1.0080
affecting extraction yield and
Surface tension (dyne cm-2)
97.76-125.43
the type of coconut kernel
Viscosity, (mPa.s)
1.61-2.02
used. It also depends on
Refractive index
1.3412-1.3446
the maturity and growing conditions, as well as whether
pH
CHEMICAL COMPOSITION (%)
or not the brown skin has been pared off.
5.95-6.30
RANGE
Moisture
73.47-76.84
Fat
18.83-21.09
Protein
2.14-2.97
Ash
0.63-0.96
Total sugars
0.82-1.62
Table 6.2 Physical properties and chemical composition of coconut milk Source: Gonzalez, 1990; Tangsuphoom, 2008.
COCONUT HANDBOOK
64 EXTRACTION YIELD DEPENDS ON A FEW FACTORS
1
2
3
4
Size of the particles
Pressure applied during pressing
Temperature
Amount of water added for extraction
When particle sizes are smaller, there is more surface area for better extraction. As pressure increases, the yield also increases. Hand pressing yields about 50% recovery of coconut milk while pressurized extraction increases the recovery of coconut milk up to 80%.
COCONUT MILK BEVERAGES Coconut milk drinks are healthy beverages. Unless it contains spraydried coconut powder and skim milk, it is naturally cholesterol free and contains healthy medium chain fatty acids. Coconut milk beverages also provide an alternative to dairy products for lactose intolerant consumers. In general, coconut milk beverages are not readily available in many countries where there is little or no coconut production of their own. As a perishable product, coconut milk beverage has limited shelf life and is easily attacked by microorganisms and bacterial enzymes when exposed to the environment. To prevent this, recombination is an alternative method of supplying a product that closely resembles fresh coconut milk to markets where the genuine article is not available. Through recombination, coconut milk beverages can be produced from coconut milk, coconut milk powder or coconut water. It can also be produced from a combination of the three, with additional ingredients like juices, flavourings and fortifications. Production methods and factors affecting coconut milk beverages are discussed in Chapters 8, 9, 11 and 12.
COCONUT OIL Coconut oil is one of the main products traditionally derived from the coconut kernel. It is a mixture of chemical compounds called triglycerides that are compounds made up of fatty acids and glycerol. Coconut oil is rich in saturated fatty acids and low in unsaturated fatty acids. The different fatty acids present in coconut can range from C6-C18 carbon atom chains. Coconut oil processing methods or technologies are classified into two major types based on copra or fresh coconut kernel used. The oil extraction technology, which starts with copra as the raw material, is commonly known as the dry process. While the method that uses fresh coconuts as starting material is generally called the fresh-wet or
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65
fresh-dry process. Based on different separation methods, coconut oil can be classified into two types – RBD coconut oil and virgin coconut oil (VCO). The former is refined, bleached and deodorized (RBD) from dry extraction, while the latter is produced by fresh-wet and fresh-dry extractions. Fatty acids composition between RBD coconut oil and VCO are similar, with the VCO regulation largely falling within the Codex specifications for coconut oil (see Table 6.3 and 6.4). PARAMETER
APCC STANDARD FOR VCO
Moisture (%)
max 0.1
Matters volatile at 120°C (%)
max 0.2
Free fatty acids (%)
max 0.2
Peroxide value (meq/kg)
max 3
Relative density
0.915-0.920
Refractive index at 40°C
1.4480-1.4492
Insoluble impurities % by mass
max 0.05
Saponification value
250-260 min.
Iodine value
4.1-11
Unsaponifiable matter % by mass, max.
0.2-0.5
Specific gravity at 30°C
0.915-0.920
Polenske value, min.
13
Total plate count
< 0.5
Colour
water clear Natural fresh coconut scent, free of sediment, rancid odour and taste
Odour and taste
Table 6.3 Essential composition and quality factors of virgin coconut oil (VCO) by APCC Source: APCC Standards for Virgin Coconut Oil
CODEX STANDARD FOR RBD COCONUT OIL
APCC STANDARD FOR VCO
C6
nd-0.70
0.40-0.60
C8
4.60-10.00
5.00-10.00
C10
5.0-8.0
4.50-8.00
C12
45.10-53.20
43.00-53.00
C14
16.80-21.00
16.00-21.00
C16
7.50-10.20
7.50-10.00
C18:0
2.00-4.00
2.00-4.00
C18:1
5.00-10.00
5.00-10.00
C18:2
1.00-2.50
1.00-2.50
C18:3
nd-0.20
<0.5
FATTY ACID
Table 6.4 Fatty acid composition of RBD coconut oil and virgin coconut oil Source: Marina et al., 2009 and APCC Standards for Virgin Coconut Oil.
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RBD COCONUT OIL Oil extracted from smoked or sun-dried copra is classified as crude coconut oil. It has high free fatty acid (FFA) values, carries a rancid odour and spots a dark colour. The crude oil is first refined by neutralization, bleaching, and deodorization (RBD) processes,
Coconut kernel is converted into copra before it is expelled and refined for oil production. This is done by first drying the kernel under the sun in an oil mill. To extract coconut oil for extensive food and industrial purposes, dry processing is used. Clean, ground and steamed copra is first pressed by wedge press, screw press or hydraulic press to obtain coconut oil, which then goes through the refining, bleaching, and deodorizing (RBD) processes. During the RBD process, heat is applied to deodorization, which is carried out at high temperatures between 204-245°C.
then packaged for sale.
During dry processing, oil is extracted by two methods – mechanically pressing or using solvents. For copra with high oil content, mechanical extraction is efficient and economical. For oil seed that requires further oil extraction from copra cake, the solvent extraction method is more suitable as it uses sophisticated equipment in large-scale operations. When oil is extracted with the mechanical method, low-pressure expellers are used. The pre-treated copra is continuously moved under increasing pressure by a worm screw in a horizontal cage of barrel made of metal bars to expel out the crude coconut oil. What is left behind is the copra cake, which can then undergo solvent extraction to extract higher oil yields. By combining both methods, oil yields are more efficient and economical than just using either one of them. When oil is extracted with the solvent method, hexane is used to dissolve the oil in copra or copra cake. The copra is steeped in hexane and allowed to percolate continuously through a bed of copra. In general, the copra moves in one direction while the solventoil mixture moves in the opposite direction.
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VIRGIN COCONUT OIL (VCO) To extract VCO on an industrial scale, fresh-wet extraction is done via a concentration stage of the coconut milk. It then goes into a phase inversion stage, followed by purification where separators are used
When fresh-wet extraction is used, VCO is obtained from coconut milk. It can be consumed in its natural state without further processing (e.g. RBD process). VCO mainly consists of medium chain triglycerides which are resistant to peroxidation. The fatty acids in VCO are distinct from animal fats which contain mainly long chain saturated fatty acids. As such, it is colourless, free of sediment and a rancid odour. It also spots a naturally fresh coconut scent.
to extract oil. Thereafter, the coconut milk undergoes drying and polishing to bring down the moisture content to 0.1-0.2%. Finally, it is packaged into bottles for consumption.
To extract VCO on a small scale, the biochemical method is used. This is based on the action of microorganisms on coconut milk, which results in the liberation of coconut oil from coconut milk emulsion. It is a simple and economical process that requires only 48-72 hours to separate the oil from the whey and protein portion of coconut milk. The enzymes and acids produced by the microorganisms trigger the separation of oil from the coconut milk. Water-white, rancid-resistant, and sweet smelling oil is produced by the action of Leuconostoc citrovorum, Streptococcus lactis, and Bacilus subtilis. A pure culture of Lactobacillus plantarum can also be used. Finally, the VCO extracted is about 90.2% oil. Through fresh-dry extraction, VCO is produced from fresh coconut kernel. This is first dehydrated to form desiccated coconut, which then goes into high pressure expellers to extract the oil. The oil then goes through a stage of setting and filtration to polish the oil into water-like clarity. In terms of physicochemical properties, VCO does not vary much from RBD coconut oil. Nevertheless, Table 6.5 shows some comparisons between VCO and RBD coconut oil. VIRGIN COCONUT OIL (VCO)
PARAMETER
RBD COCONUT OIL
Colour
Colourless
Yellow
Aroma
Similar to fresh coconut
No perceptible aroma
Acid, cocojam (aroma associated with roasted coconut), latik (aroma of cooked coconut with sweet sensation), nutty and rancid aromas Flavour
Sweet taste and nutty flavour
No perceptible flavour
Phenolic content
Higher
Lower
Antioxidant activity (%)
71
56
Table 6.5 Comparison between Virgin Coconut Oil and RBD Coconut Oil
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COCONUT FLOUR Coconut flour is a screened food grade product obtained after drying, expelling and extracting most of the oil or milk from sound coconut meat. It is cream coloured and less white than all-purpose flour. With a slightly nutty odour, it tastes almost bland, due to its reduced fat content. It is classified according to fat (low, medium and high), protein (high protein) and fibre (high fibre) (see Table 6.6). In general, coconut flour can either be processed from fresh coconut kernel, or obtained as a by-product after milk extraction.
CLASSIFICATION OF COCONUT FLOUR
DESCRIPTION
Whole, full fat
From unpared, dehydrated and edible coconut kernels by pre-pressing and solvent extraction.
From pared coconut meat
From pared, dehydrated and edible coconut kernel.
Defatted
Obtained from food grade copra, defatted by solvent or mechanical extraction. Brownish in colour.
Low fat Medium fat High fat
10-15% fat content 16-25% fat content 25-48% fat content
Low-fat, high fibre
From finely grounded coconut flour residue called “sapal”. Fat content of the resulting flour ranges from 10-15%, and has a total dietary fibre content of more than 60%.
High-protein, high fibre
Prepared from dehydrated, finely grounded coconut meat.
Paring flour
Prepared from the paring or testa of the coconut.
Copra meal
Obtained after extracting oil for granulated copra.
Table 6.6 Sub-classifications of coconut flour Source: Philippine Coconut Authority, 2010
COCONUT MILK POWDER Coconut milk powder is spray-dried coconut milk. Similar to instant milk powder, it is white in colour, free flowing and easily dispersed in water. It also has an acceptable coconut flavour. Powdered coconut milk contains about 61% oil, 27% carbohydrates, 7% protein, 1.8% ash, 0.2-0.8% moisture and 0.02% crude fibre. It can be easily reconstituted into coconut milk by adding water and used directly in food recipes. For coconut milk to be spray-dried into powder, it must first be mixed with maltodextrin and casein (sodium caseinate or skim milk). This is because maltodextrin is required in the spray drying operation, while casein prevents lumping of the coconut milk powder due to its high fat content reaching up to 79%. With casein, the protein encapsulates the small oil droplets which prevents them from lumping together, forming a powdery product.
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DESICCATED COCONUT Desiccated coconut is produced from the kernel of fully matured coconuts. Rich in oil and taste, it is a commonly found ingredient in the confectionary industry for many baked foods, chocolates, candies and even ice cream. For over 70 years, it is a traditionally exported commodity, and is one of the most important commercial products from coconut. As it is made directly from coconut meat, desiccated coconut retains the original oil and protein of a fresh mature coconut. To produce desiccated coconut, fresh mature coconut kernel is first pared down to remove the brown skin and any infected meat. The white kernel is then rinsed and sterilized to eliminate bacteria, including Salmonella which cases food poisoning. To sterilize, the meat can be pasteurized at 80-90°C in 2% sodium metabisulphite solution for 20 minutes. It can also be passed through a large tank containing boiling water or subjecting the pieces of meat to live steam in stainless steel blanchers at 80°C for five minutes. The pasteurized kernel is then sent to the disintegrators or cutters where it is cut and then shredded into a fine, wet meal. The cutters have adjustable provisions so that shredded coconut meat of different sizes can be obtained. The wet meal is then dried by spreading it out on trays which are then mounted in tiers in a hot-air drier. It can also be dried in a continuous dryer with two stages where the material is turned over from the first to the second stage. This is done until it reaches a low moisture content of about 2.5-3.5%. Different sizes of desiccated coconut is then mixed and conveyed to a sieving machine, where different particle sizes are separated and bagged into 50kg bags. Alternatively, desiccated coconut is produced from the by-product of coconut milk production. The wet meal that is left after coconut milk has been extracted from the wet kernel is still a good source of fibre, protein, and oil. It can go through further shredding, or go straight into the dryer and dried until it reaches a low moisture content. As a result, such desiccated coconut has lower fat levels and can be classified as defatted desiccated coconut. In general, there are four different grades of desiccated coconut classified according to coarse, medium, fine and superfine sizes.
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The required specifications for desiccated coconut are not uniform across all markets. Each exporter or importer has his own standards and requirements. The Codex definition on desiccated coconut is seen in Table 6.7. In some markets where sulphite treatment is carried out, it is specified by some buyers that the residual level of sulphite is no more than 15-100ppm, or sulphite-free. PARAMETERS
REQUIREMENTS
Total acidity of the extracted oil
≤ 0.3% m/m measured as lauric acid
Moisture
≤ 4% m/m
Oil content
≥ 60% m/m for desiccated coconut from coconuts without oil extraction ≥ 35 and < 60% m/m for desiccated coconut from coconuts which have had partial oil extraction
Ash
≤ 2.5% m/m
Extraneous vegetable material: Harmless vegetable matter associated with the product
≤ 15 fragments per 100g
Foreign matter: Any visible and/or apparent matter or material not usually associated with the product
Absence in 100 g
Table 6.7 Chemical and physical characteristics of desiccated coconut Source: CODEX STAN 177-1991
CHAPTER 6 | COCONUT FOOD PRODUCTION
NATA DE COCO Ingredients for culturing 1 kg of nata • 12 cups (3 kg) of coconut water (or milk of one coconut in 12 cups of water)
• 2 cups of mother liquor • 1/4 cups of glacial acetic acid
71
Mother liquor, containing Acetobacter xylinum, is obtained from a previous culture. Stocks of freeze-dried mother liquor are usually held at government institutions engaged in industrial development or research.
NATA DE COCO Nata de coco is a gelatinous dessert with a clear, smooth and chewy texture. It is composed of cellulose produced by the action of an acidic medium called Acetobacter xylinum on coconut water or diluted coconut milk. ‘Nata’, when formed, is sweetened by cooking in thick sugar syrup. After production, nata de coco is bottled for local consumption and exported to the Philippines, Thailand, Indonesia, and Sri Lanka. First, coconut water or diluted coconut milk is filtered and boiled to kill off contaminants. Next, the filtered mixture is cooled. Then, a cup of sugar is dissolved and added into the mixture along with mother liquor and acetic acid. Finally, the mixture is poured into culture jars to a height of 60 mm, covered with clean paper and incubated between 23-32°C, optimally at 28°C. The jars are left undisturbed, so that the nata formed at the surface will sink to the bottom. After eight to 10 days, nata is picked out with a clean fork when it is about 25 mm thick. Care should be taken not to contaminate the mother liquid below the nata formation, as it will be used again as a culture in the next production of nata. It is then cleaned by removing the creamy, acid formation at the bottom and cut into squares of about 20 mm. It is then washed and boiled for one minute in an open pan, drained, and soaked in water that is changed constantly. This is repeated until the acidic taste is removed. Finally, the nata is drained over a two hour period. Sugar syrup is prepared using two cups of sugar with one cup of water. Last but not least, the product is kept overnight when the nata and colouring are added. The next day, the nata is cooked until the gummy texture is removed and becomes relatively transparent. Flavouring is added and nata bottles are filled with 75% nata and 25% sugar syrup. For packaging, the bottles are tightly sealed with seal caps and processed in boiling water for 30 minutes, then dried and cooled before storage. When produced on an industrial scale, large, 200 litre drums are used to mix the acid, coconut water or diluted coconut milk with mother liquor and sugar. Nata is also set in moulding containers about 2-3 cm thick.
RECIPES
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Coconut water and milk can be combined with other ingredients in cooking. Here are some delicious in-home recipes for reference.
BEVERAGES (2 SERVINGS) COCONUT MILK BEVERAGE Delicious alternative to dairy milk
COCONUT SOY BEVERAGE Delicious alternative to dairy milk
1-2 tablespoon coconut milk or cream
1-2 tablespoon of coconut milk
1 cup coconut water
1 cup of soy milk
Sugar and 1 teaspoon chocolate powder to taste
Sugar or honey to taste
Stir all ingredients well. Best served chilled.
Blend all and serve chilled immediately.
HANGOVER CURE
COCONUT AND CRANBERRY FLUSH
Hydrates the body quickly and safely
Maintains good urinary health
1 green tea bag
2 cups coconut water
2 cups coconut water
2 cups cranberry juice
Bring coconut water to boil in a saucepan. Take off heat. Steep the green tea bag in hot coconut water for 3-4 minutes. Blend well and serve immediately.
GREEN HELPER
Balances an “over-acidic” body 1 medium cucumber 1 large red apple 2 cups coconut water 6 carrots 6 stalks celery Handful of ice cubes Run the cucumber, red apple, carrots and celery stalks through the juicer. Mix fresh juices well with coconut water. Add ice and serve immediately.
COCONUT WATER AND WATERMELON COOLER
Rehydrates and cools on a hot day 1 cup coconut water 1 fresh lime, juiced 1 tablespoon honey 2 cups fresh watermelon chunks without seeds Blend until smooth and serve immediately.
Blend well and serve immediately.
STRAWBERRIES AND PINEAPPLE SMOOTHIE
Healthy liquid breakfast packed with antioxidants and other immune-boosting properties
1 cup coconut water 1 cup pineapple chunks 1 teaspoon honey (more to taste) 2 cups halved strawberries 2 cups crushed ice Some cubed coconut kernel Combine all ingredients in blender and process until smooth. Divide smoothie between 2 glasses and serve chilled.
MEALS (4 TO 6 SERVINGS) CHICKEN AND BARLEY SOUP Nourishes the soul
½ cup pearl barley 1 chicken, cut into large pieces 1 onion, chopped 2 large carrots, chopped 2 stalks leek, chopped 8 cups coconut water Powdered chicken stock, to taste Sea salt flakes and freshly ground pepper, to taste Chopped parsley for garnishing Fill a large pot with coconut water and add the chicken pieces. Cook on low heat until chicken is tender. Remove chicken from broth and set aside until cool enough to handle. Cool broth and skim off chicken fat. Remove meat from bones; discard bones and shred meat. Set aside. Add vegetables and barley to the broth and bring to a boil. Reduce heat; cover and simmer for 1 hour or until vegetables and barley are tender. Add shredded chicken to broth during the last 10 minutes of cooking. Season with salt and pepper to taste. Serve hot with chopped parsley as garnish.
CHICKEN CURRY Satisfies a hearty appetite
½ cup coconut milk ½ onion, diced 1 oz (25 g) curry powder for meat 1 big tomato, cut into wedges, optional 1 ½ lbs chicken, chopped into pieces 2 small potatoes, peeled and cut into wedges 2 tablespoon oil 3 cups water 4 hard-boiled eggs, optional Salt to taste Heat oil in a pot. Stir-fry onions until aromatic, add curry powder. Stir a few times, then add the chicken, stir to combine for about 1 minute. Add the water into the pot and bring it to boil. Lower the heat, add tomatoes, potatoes and eggs. Cover the pot, simmer for 30-45 minutes or until chicken is tender. Add coconut milk and salt to taste, simmer for another 5 minutes. Dish out and serve immediately with steamed rice.
DESSERTS (2 SERVINGS) COCONUT JELLY
Healthy, low-fat sweet indulgence
3 cups coconut water 3½ tablespoon gelatine 1½ cup sugar 1 tablespoon lemon juice ½ cup coconut milk to coat ½ cup melted coconut palm sugar (Gula Melaka) to coat 1 teaspoon of toasted grated coconut Dissolve sugar in 2 cups of coconut water Heat 1 cup coconut water over low heat, add in gelatine and mix until fully dissolved Strain coconut water-gelatine blend into coconut water sugar blend. Add in lemon juice and gently mix. Pour into individual moulds and chill it with the required time. Serve with freshly squeezed coconut milk and melted palm sugar (or Gula Melaka) drizzled over Garnish with toasted grated coconut to own preference. Alternatively, substitute the liquid used to make your favourite jelly recipe with coconut water.
KAYA
Coconut egg jam
½ cup coconut cream ¾ cup coconut milk 1½ tablespoons corn starch 1½ tablespoons water 3 pandan leaves, tied into a knot 4-5 eggs 50-75g sugar, dissolved to make caramel 200g sugar Crack the eggs into a big bowl, whisk well with coconut cream, coconut milk, and sugar. Filter the mixture with a strainer and transfer the egg mixture into a sauce pan. Add pandan leaves into egg mixture and turn on the heat to medium low. Using a wood spatula or a pair of wooden chopsticks to stir the mixture until they are cooked for about 20 minutes. To thicken the kaya, add corn starch mixture and stir. At the same time, heat the sugar in a sauce pan until it melts into caramel. Add the caramel into the kaya, stir to combine. The colour of the kaya should be golden brown. Let the kaya cool and discard pandan leaves. Blend the mixture until a silky smooth consistency is reached. Keep refrigerated and use within a week.
CHAPTER 7
THE CHEMISTRY OF COCONUT WATER Coconut water is a natural, fat-free drink. Low in sugars and calories, it is rich in essential electrolytes and vitamins. Dubbed the “fluid of life”, coconut is safe for everyone to drink fresh from the nut.
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THE CHEMISTRY OF COCONUT WATER Coconut water is a natural, fat-free drink. Low in sugars and calories, it is rich in essential electrolytes and vitamins. Dubbed the “fluid of life”, coconut is safe for everyone to drink fresh from the nut. As the Hawaiians say, coconut water is “dew from the heavens”. Once the coconut is opened, coconut water begins to lose its nutrients and flavours. This is partly due to naturally occurring enzymes found in coconut water. When peroxidase (POD) and polyphenol oxidase (PPO) come into contact with oxygen, reactions cause nutritional and flavour losses. This section covers the reactions that happen when coconut water is extracted and loses protection of the coconut’s sterile environment.
COMPOSITION OF COCONUT WATER Analytical studies have shown that coconut water contains nutrients such as glucose, amino acids and electrolytes such as potassium, calcium and magnesium (Table 7.1). While the composition of coconut water was covered in Chapter 3, it is important to recall the differences in the composition of coconut water obtained from young (7-9 months) and mature (10-13 months) coconuts. The composition, physicochemical, PPO and POD enzyme activities are influenced by factors such as geographical location and variety. The compositional differences relate to the effects deterioration reactions have as well as the quality aspects of coconut water. In general, young coconuts have higher sugar levels and total phenolic contents than mature coconuts. While mature coconuts have higher protein levels and pH values than young coconuts, the amount of minerals can also vary between young and mature coconuts. For example, the amount of potassium in coconut water increases as the coconut matures.
CHAPTER 7 | THE CHEMISTRY OF COCONUT WATER
PHYSICOCHEMICAL PROPERTIES
COCONUT MATURITY STAGE (MONTHS) 5-6
8-9
≥12
Volume of water (mL)
684
518
332
Total soluble solids (°Brix)
5.6
6.15
4.85
Titratable acidity (%)
0.089
0.076
0.061
pH
4.78
5.34
5.71
0.031
0.337
4.051
1
Turbidity
2
77
SUGAR CONTENT Fructose (mg/mL)
39.04
32.52
21.48
Glucose (mg/mL)
35.43
29.96
19.06
Sucrose (mg/mL)
0.85
6.36
14.37
220.94
274.32
351.10
Sodium (mg/100 mL)
7.61
5.6
36.51
Magnesium (mg/100 mL)
22.03
20.87
31.65
Calcium (mg/100 mL)
8.75
15.19
23.98
Iron (mg/L)
0.294
0.308
0.322
Protein (mg/mL)
0.041
0.042
0.217
Total phenolic content3 (mg/L)
54.00
42.59
25.7
MINERALS Potassium (mg/100 mL)
Table 7.1 Physicochemical properties of coconut water Titratable acidity expressed as malic acid percentage Turbidity expressed as absorbance reading at 600 nm 3 Total phenolic content expressed as mg GAE/L Source: Tan et al., 2014 1 2
PROPERTIES AND REACTIONS OF COCONUT WATER FLAVOUR Flavour is the complex experience of smell, taste and mouthfeel. The flavour profile of coconut water is built from acids, sugar, phenolic compounds and mineral content. Coconut water extraction, formulation, processing and storage can also affect the flavour. Between 7-9 months, the sweetness of coconut water increases to its maximum when sugar content increases. From 10-13 months, the sugar levels decrease and coconut water tastes less sweet. This is represented by total soluble solids (°Brix). Left at a room temperature of 25°C, fresh coconut water turns sour, as various oxidative and fermentative reactions occur. This forms acids as products. To maintain the acceptability of fresh coconut water, it should be kept under chilled condition at all times.
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In general, acidity of coconut water decreases with maturity, and this contributes to the increasing sweetness of coconut water between seven to nine months. The phenolic content also contributes to the overall flavour profile of coconut water. It decreases with maturity, hence mature and young coconut water tastes significantly different. When oxidized, the polyphenols can also lead to a complex reaction, resulting in the undesired discolouration of coconut water. Rancidity Rancidity refers to developing off-flavours when the hydrolysis, oxidation or microbial degradation of lipids form free fatty acids (FFA), which subsequently undergoes further reactions and yield offflavoured ketones. While coconut water does not contain much oil content, the lipids present may cause rancidity. Depending on the number of carbons, these ketonic compounds give different off-flavours. For example, heptan-2-one gives a rancid almond flavour while nonan-2-one gives a turpentine flavour (Kellard et al., 1985). For more details, please refer to Chapter 8 on lipid oxidation and lipolysis. APPEARANCE Coconut water is a relatively clear, colourless liquid. Its appearance is affected by coconut maturity and environmental exposure. Turbidity Turbidity refers to the extent which coconut water appears to be unclear. Naturally, it increases as coconuts mature. In addition, turbidity is influenced by the total dissolved sugars, proteins, and other matters. It is also affected by the count of microorganisms when coconut water is exposed to the environment upon extraction. When this happens, microorganisms multiply and contribute to the increasing turbidity of coconut water. Hence, if a young coconut water is left exposed with no control measures like cooling, it can turn as turbid as mature coconut water in a matter of hours. Colour Browning Due to high oxidation and heat, coconut water can turn from clear or slight white turbidity to brown. This is brought by complex reactions in its components. Typically, it is caused by phenolic oxidation, Maillard reaction and caramelization. These browning reactions are also found in other beverages like green tea, apple and sugar cane juices. The quality of coconut water is preserved when these reactions can be retarded or stopped completely.
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Enzymatic phenolic oxidation Enzymatic browning is one of the most important colour reactions that affect fruits, vegetables, and seafood. When coconut water is extracted, its exposure to air initiates reactions like oxidation. This is promoted by enzymes polyphenol oxidase (PPO) and peroxidase (POD) which are naturally present in coconut water. When enzymes catalyse, the oxidation of phenolic compounds present in coconut water form brown pigments. In Table 7.2, the assessment shows that the enzyme activity of PPO is higher than POD. PPO is also more heat resistant than POD. In the case of coconut water, PPO is used as the indicator for enzyme deactivation treatments.
1
ENZYME ACTIVITY (U mL-1 °Brix-1 min-1)
COCONUT MATURITY STAGE (MONTHS) 5-6
8-9
≥12
Peroxidase (POD)
0.052
0.117
0.129
Polyphenol oxidase (PPO)
0.543
0.160
0.056
Table 7.2 Enzyme activity according to coconut maturity 1 A unit of enzyme activity refers to the amount of enzymatic extract necessary to produce an increase of absorbance at rates of 0.001 unit per millilitre of sample per soluble solids content per minute (U mL-1 °Brix-1 min-1 ). Source: Tan et al., 2014
Non-enzymatic phenolic oxidation Without PPO and POD enzymes, phenolic browning can still occur when oxygen is present. This takes place at a reduced rate in coconut water. Maillard reaction Maillard reaction causes proteins to deteriorate when food is processed and stored. This reaction can promote the loss of nutritional quality when essential amino acids are destroyed. It also reduces protein digestibility and amino acid availability. Maillard reaction covers a whole range of complex transformations. Starting with a reaction between a reducing sugar like glucose and an amino acid, it ends with the formation of melanoidins which are brown, high molecular weight heterogeneous polymers.
OTHER TYPES OF BROWNING
1
Vitamin C browning is caused by its degradation products from both aerobic and anaerobic pathways of Vitamin C.
2
Gallic acid browning can occur as coconut water contains a considerable amount of gallic acids, which can serve as a substrate in enzymatic browning reaction (Maciel et al., 1992). Oxygen is required to forward the reaction. (Jangchud et al., 2007).
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Caramelization Caramelization of carbohydrates occurs when surfaces are heated strongly, such as baking and roasting. It also occurs when foods with high sugar content, such as jams and certain fruit juices, are processed. Browning in caramelization is due to the formation of caramels, a complex mixture of various high molecular weight components. They can be classified into three groups: Due to its low sugar content, a very small extent of caramelization takes place when coconut water undergoes heat treatment.
1
CARAMELANS C24H36O18
2
CARAMELENS C36H50O25
3
CARAMELINS C125H188O80
Pinking of coconut water Pinking is a phenomenon that happens only in young coconut water. Pinking is due to the intermediate compounds formed from the enzymatic phenolic oxidation of coconut water. Compared to mature coconut water, young coconut water consists of a higher phenolic content, PPO and POD enzyme activity (refer to Table 7.2 for the differences between these enzyme activities). In the primary process, PPO catalyses the oxidation of phenolic compounds to form brown polymers (Villamiel et al., 2006). The substance which causes pinking is an intermediate in this reaction, i.e. o-quinone (Mathew et al., 1971). In the secondary process, this pink or red compound can further react with amino acids to form more compounds like p-amino-o-quinone (Mathew et al., 1971). NUTRIENTS Coconut water contains many water-soluble vitamins (see Chapter 3, Table 3.4). In particular, Vitamin C is a sensitive compound in coconut water. It reacts with oxygen, and its loss is consequently closely related to the availability of oxygen in packages. In general, Vitamin C is lost through anaerobic and aerobic degradations. Anaerobic and aerobic degradations Both anaerobic and aerobic degradations take place simultaneously. Which one predominates the other depends on storage temperature and the availability of oxygen.
Losses caused by aerobic degradation pathway cannot be prevented by packaging, which is consistent for all types of package. The only possible countermeasure is to reduce the storage temperature.
As the name implies, the anaerobic pathway does not need oxygen. It is mainly driven by storage temperature. For aerobic degradation, the pathway needs oxygen. This is strictly related to the presence of headspace oxygen, the dissolved oxygen in coconut water, and the oxygen barrier properties of the package.
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EFFECTS OF ENVIRONMENTAL FACTORS AND ADDITIVES ON QUALITY Raw, natural, unprocessed coconut water affects the final quality of the packaged product. While there are ways to preserve and maintain the quality of the raw material, it is not possible to improve it. POST-HARVEST STORAGE To increase shelf life, tender and mature coconuts should be harvested carefully. The perianth should remain intact, and the nuts should not be broken or cracked. Compared to partially dehusked nuts, the quality of coconut water from non-dehusked nuts can be maintained for an extended period of time. After harvesting, the husk of the coconut helps to minimize the above changes in the coconut water over the storage period. The husk also acts as added protection from cracks that would lead to the contamination and eventually spoilage of coconut water. As the husk helps to preserve nut quality and increase the storage life of coconut water, the taste of stored dehusked nuts can subsequently become less desirable than non-dehusked nuts. Over a period of storage:
1
2
3
Volumes of coconut water in the intact nuts decline
Sugar content (°Brix) of coconut water increases
Acidity decreases and turbidity increases
EXTRACTION METHODS Different extraction methods, like drilling or halving the nuts, vary the effect on coconut water extraction. This is because young and mature coconuts have different husks and shells. In drilling, there is generally less contamination by coconut fibres, soil and enzymes from the other parts of the coconut. However, the likelihood of contamination increases for mature coconuts. As the fibres are drier and shells are harder, it is easier for them to fall into extracted coconut water. This is why right after extraction, filtration is an important step to remove the contaminants.
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To balance between both heat effects on coconut water, factors across the whole chain like raw material quality, hygienic handling and even governmental regulations need to be taken into account when
HEAT Heat has positive and negative effects on coconut water, depending on the range of temperature and the parameter under observation. In general, an increase in temperature results in an increase in reaction rates. At certain temperature ranges, this may lead to negative effects such as browning and microbial multiplication. Hence, coconut water should be cooled down to below 4°C after coconut water extraction and filtration.
processing and packaging coconut water.
On the other hand, proper application of heat treatment results in positive effects on coconut water. For example, heat can be used for enzyme deactivation, pasteurization or sterilization to kill off pathogens and spoilage microorganisms. Specifically, in direct heat treatment like steam injection, the temperature quickly rises and falls at the start and the end. Thus, there is less thermal impact than indirect heat treatment. As a result, coconut water that undergoes indirect heat treatment becomes browner at the start of their packaged shelf life. Based on its browning index, it also has a shorter shelf life. For more information on direct and indirect heat treatments, please refer to Chapter 11. MATURITY AND STORAGE TEMPERATURE Between young and mature coconut water, the latter spoils faster. As compared to the former, the quality parameters like pH and turbidity are sub-par. There is also likely to be more contamination in mature coconuts, as more husk and shell pieces fall into the extracted water during drilling. In addition, mature coconut water is typically more turbid than young coconut water at any stage of storage. As temperature increases from 4-35°C during storage, there is a faster change in the total soluble solids content, pH, and titratable acidity of untreated coconut water. There are also noticeable visual changes for mature coconut water. For example, turbidity increases, browning occurs and pH decreases. OXYGEN EXPOSURE With oxygen exposure, aeration accelerates pinking and browning. This is due to oxidation of polyphenols which are catalysed or otherwise. Thus manufacturers often add antioxidants like ascorbic acid and sodium metabisulphite to scavenge oxygen, making it unavailable for other reactions. Alternatively, nitrogen blanketing may be used in storage and aseptic tanks, where sterile air is replaced with nitrogen. As a result, the air in the headspace contains 99.9% nitrogen, an increase from an initial content of 78% nitrogen and 21% oxygen.
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ANTIOXIDANTS Antioxidants are often added to control discolouration. It also helps to extend coconut water’s shelf life. They work by scavenging oxygen or free radicals. Commonly used, the two effective antioxidants
L-ascorbic acid (Vitamin C) Ascorbic acid, otherwise known as Vitamin C, plays an important role in food processing. Vital for human nutrition as well, its key antioxidant effect acts as an inhibitor of enzymatic browning. This has been widely used in the food industry. However, with high ascorbic acid levels and the presence of oxygen, browning may also occur. This is due to the thermal decomposition of ascorbic acid.
for coconut water are ascorbic acid and sodium metabisulphite.
By its very nature, coconut water does not contain much ascorbic acid. However, when ascorbic acid is added as an antioxidant, close attention must be paid so its level does not get so high that it promotes ascorbic acid browning instead. In general, ascorbic acid levels of 20-50 ppm can help to minimize enzymatic browning. Sodium metabisulphite (SMB) When oxygen reacts with SMB, it becomes unavailable for other browning reactions. Sulphite also reduces o-quinone, which is produced by PPO catalysis, to a less reactive diphenol. This prevents later condensation of complex brown melanins. While most countries regulate the presence of SMB in coconut water at 30 ppm maximum, it is advisable to check with local authorities on the most recent permissible levels of this antioxidant.
MICROBIOLOGY OF COCONUT WATER A specific microorganism’s activity is governed by the enzymes it possesses, as these
Microorganisms are frequently used in producing food products like cheese and yoghurt. However, certain microorganisms can cause food poisoning, human disease, and spoilage.
determine what it can feed on, break down, and also what end-products it produces.
During the extraction of coconut water from mature coconuts, oil from the kernel can enter the coconut water. These minute amounts of oil, if broken down, can result in a rancid taste profile.
In microorganisms, there are many biochemical and enzymatic systems concerned with coconut water and its products. These can be subdivided into which constituents they break down into and their respective effects. BREAKDOWN OF OIL Fat is broken down by enzymes (mainly lipase) in a process called lipolysis into free fatty acids. Through normal processing routines like pumping, stirring and splashing, there is a higher chance for lipase to work on the oils. While some of the fatty acids produced are volatile, give off strong smells, or contribute to a sour taste, many bacteria and moulds that break down proteins also break down oil through oxidation. Lipolysis is covered in more detail in Chapter 8.
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BREAKDOWN OF CARBOHYDRATES The microorganism’s enzymes determine which carbohydrates they can break down into, and to what extent. While fermentation occurs in most cases, carbohydrates can be completely degraded to carbon dioxide and water through oxidative metabolism. Usually, fermentation produces organic acids (e.g. lactic and butyric acids), alcohols (e.g. ethyl and butyl) and gases (e.g. carbon dioxide and hydrogen). In general, carbohydrate fermentation results in the production of acid (souring, pH drop) and gases, depending on the organisms (Table 7.3). CONDITION Presence of oxygen Absence of oxygen - Alcoholic fermentation - Butyric acid fermentation - Lactic acid fermentation i) Homofermentative ii) Heterofermentative
PRODUCTS CO2 + water + energy Ethanol + CO2 Butyric acid + CO2 +H2 Lactic Acid Lactic acid + ethanol + acetic acid + CO2
Table 7.3 Microbiological carbohydrate metabolism products Source: © Tetra Pak International S.A., Dairy Processing Handbook 2015
When carbohydrates breakdown in coconut water, it turns sour and have an unacceptable odour. BREAKDOWN OF PROTEIN Proteins break down in a process called proteolysis, which involves the enzymes called proteases. When they degrade proteins into peptides, they are further degraded by various peptidases to smaller peptides and amino free acids. While amino acids can be reused again for protein synthesis to grow or multiply microorganisms, they can also be broken down by oxidation or fermentation processes. Proteins and their constituent amino acids have a wide combination of chemical elements. They contain carbon, hydrogen, oxygen, sulphur, nitrogen and phosphorus. Therefore, the breakdown of protein results in a much larger range of acids, alcohols, gases like hydrogen, carbon dioxide, hydrogen sulphide, ammonia, and other compounds. In particular, ammonia, which is alkaline and has a strong odour, is always produced. For more information on proteolysis, please refer to Chapter 8. As coconut water contains trace amounts of sulphur-containing amino acids (e.g. methionine and cysteine), the breakdown of these amino acids may produce hydrogen sulphide, which gives off a rotten egg smell.
CHAPTER 8
THE CHEMISTRY OF COCONUT MILK AND CREAM Coconut milk and cream is a white, opaque protein-oil-water emulsion used in many traditional Asian cuisines. It is a milky fluid obtained by manually or mechanically extracting fresh kernel.
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THE CHEMISTRY OF COCONUT MILK Coconut milk and cream is a white, opaque protein-oil-water emulsion used in many traditional Asian cuisines. It is a milky fluid obtained by manually or mechanically extracting fresh kernel. The quality attributes are affected by many factors, such as the variety of nuts, water quality and volume used for coconut milk extraction. Due to its high oil content, coconut milk products are highly susceptible to chemical and biochemical spoilage, like lipid oxidation. For coconut milk and cream products, fat content is the important criteria for categorization. According to Codex Standards for Aqueous coconut products (CODEX STAN 240-2003), coconut milk should contain at least 10% fat, 2.7% non-fat solids, and 12.7-25.3% total solids. For coconut cream, it should contain at least 20% fat, 5.4% non-fat solids and 25.4-37.3% total solids (Table 8.1).
TOTAL SOLIDS (%m/m)
NON-FAT SOLIDS (%m/m)
FAT (%m/m)
MOISTURE (%m/m)
pH
MIN. - MAX.
MIN.
MIN.
MAX.
MIN.
Light coconut milk
6.6-12.6
1.6
5
93.4
5.9
Coconut milk
12.7-25.3
2.7
10
87.3
5.9
Coconut cream
25.4-37.3
5.4
20
74.6
5.9
Coconut cream concentrate
37.4 min.
8.4
29
62.6
5.9
In general, the fat content in packaged coconut milk and cream products from ASEAN
PRODUCT
ranges from 17-25%.
Table 8.1 Classification of coconut milk and cream Source: CODEX STAN 240-2003
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COMPOSITION OF COCONUT MILK For the ease of understanding, coconut milk refers to both coconut milk and cream products.
The composition of coconut milk is affected by the composition of coconut kernel. It is important to highlight that the difference in oil content at various ages of the coconut kernel relates to the yield and quality of coconut milk obtained (see Chapter 3, Table 3.6). While a young coconut at eight to nine months old has only about 18-26% oil content, a mature coconut at 10-13 months has up to 43% oil content. As a result, these mature coconuts are typically harvested for coconut milk production. Other than the age and type of the coconut, the composition of coconut milk (Table 8.2) is also dependent on the extraction process (refer to Chapter 6). PHYSICAL PROPERTIES
RANGE
Specific gravity
1.0029-1.0080
Surface tension (dyne.cm-2)
97.76-125.43
Viscosity, (mPa.s)
1.61-2.02
Refractive index
1.3412-1.3446
pH
5.95-6.30
CHEMICAL COMPOSITION (%)
RANGE
Moisture
73.47-76.84
Fat
18.83-21.09
Protein
2.14-2.97
Ash
0.63-0.96
Total sugars
0.82-1.62
Table 8.2 Physical properties and chemical composition of coconut milk Source: Gonzalez, 1990; Tangsuphoom, 2008.
Coconut milk is a very rich medium that supports the growth of common spoilage microorganisms, usually introduced via contaminated shells, utensils, processing equipment and handlers.
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PROPERTIES AND REACTIONS OF COCONUT MILK Like coconut water, the properties of coconut milk are affected by extraction, formulation, processing and storage. Its flavour profile is built up from acids, protein, sugars, phenolic compounds, mineral content and oil content. Its appearance is mainly affected by colour reactions and the amounts and size of the oil globules. Chemical deterioration (mainly lipid autoxidation and lipolysis) and microbiological degradation are the two major reactions that affect the quality of coconut milk. Similar to coconut water, coconut milk is also affected by browning reactions. As a result, the white milky colour turns slightly greyish. CHEMICAL DETERIORATION (LIPID OXIDATION AND LIPOLYSIS) When chemical deterioration occurs, lipid oxidation and lipolysis of unsaturated and saturated fatty acids in coconut milk results in objectionable taste and odours. The hydrolysis of triglycerides can be particularly rapid when catalysed by the lipase enzyme. The release of short-chain fatty acids, specifically butyric, caproic, caprylic, and capric acids, can give rise to strong off odours. Medium-chain fatty acids, such as lauric and myristic acids that are typical of coconut oil also produce a distinctive soapy taste. Lastly, oxidative rancidity occurs when unsaturated fatty acids are oxidized. The oil content of coconut milk is characteristically made up of medium chain triglycerides of saturated fat. About 5.5% of the oil content is monounsaturated fatty acids and another 2% is polyunsaturated fatty acids. These triglycerides are susceptible to hydrolysis into free fatty acids by lipoxygenase and lipase enzymes, which are naturally present in coconut milk. DISCOLOURATION Similar to coconut water, discolouration reactions in coconut meat are caused by enzymatic (polyphenol oxidase, PPO and peroxidase, POD) reactions (Siriwongwilaichat et al., 2004). This results in discolouration of the coconut milk. Discolouration reactions in coconut milk are also non-enzymatic browning. The colour, turbidity, and opaque appearance of coconut milk is also affected by the size of the dispersed oil globules which have light scattering properties. In general, when oil globules are smaller, the reflectance increases, imparting a whiter colour to coconut milk.
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SEPARATION Depending on consumer perception, the separation of coconut milk into two layers is quite subjective. When left to stand, coconut milk tends to separate into an oil-rich top and a water-rich bottom. When used to cook traditional Asian cuisine, coconut milk can also contribute to the final taste and look of the dish. In most ASEAN countries, consumers perceive dishes to be of good quality when it comes with a layer of oil at the top (Figure 8.1). However in Sri Lanka, the same dishes are perceived to be of bad quality (Figure 8.2).
Figure 8.1 Spicy chicken curry
Figure 8.2 Anchovy fish curry
Coconut milk is an oil-in-water emulsion (Figure 8.3). This means that coconut milk is insoluble or miscible in water, and has a fine dispersion of minute droplets of coconut oil in water. In addition, the emulsion may also contain emulsifiers and thickening agents that hold these two phases together. Coconut milk has naturally occurring proteins like globulins and albumins, as well as phospholipids like lecithin and cephalin to act as natural emulsifiers. To some extent, these help to stabilize the emulsion, serving as the surface between oil and water.
Figure 8.3 An oil in water emulsion. © Tetra Pak International S.A., Dairy Processing Handbook 2015
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As with all emulsions, coconut milk is physically unstable and prone to phase separation as the protein content and quality in coconut milk is not enough to stabilize fat globules (Figure 8.4). Emulsion stability is quantified by the creaming index of coconut milk samples, which results from the action of gravitational force on phases with different densities. A higher creaming index indicates the tendency to aggregate oil droplets, which destabilizes and separates the emulsion (Figure 8.4). Flocculation is another destabilizing mechanism for emulsions, as fat globules move as groups rather than as individuals. This increases the chances of creaming. Contrary to flocculation, coalescence involves the rupture of interfacial film, a joining of globules, and a reduction in the interfacial area (Figure 8.5). Contact of globules must preclude coalescence, and this can occur through flocculation, creaming (Figure 8.4), or Brownian movements when particles move randomly. Typically, the use of emulsifiers and thickening agents (stabilizers) at levels less than 2% with homogenization can improve emulsion stability of coconut milk.
Figure 8.4 Separation of oil in water through creaming, coalescence and flocculation
Figure 8.5 Coalescence of oil particles
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Emulsifiers are amphiphilic, surface-active substances that help to retard the phase separation. This is done by absorbing to the oilwater interface, thereby lowering the interfacial tension. Proteins that naturally occur in coconut can act as emulsifiers. For commercial production, emulsifiers can be added to improve the stability for longer product shelf life. Thickening agents or stabilizers are hydrocolloid materials that provide stabilization for emulsions, suspensions and general thickening properties. They are used widely for their unique textural, structural, and functional characteristics in food. Many do not function as true emulsifiers as they lack the necessary combination of strong hydrophilic and lipophilic properties in a single molecule. Instead, they stabilize the emulsions by thickening or increasing the viscosity of the product. This lowers the rate of separation between the oil and water layers. PROTEIN INTERACTIONS Small amounts of protein in coconut milk act as natural emulsifiers. As charged and surface-active molecules, they can help formulate and improve the stability of oil-in-water emulsion. Absorbing at the surface of the droplets, protein provides repulsive interactions like electrostatic and steric effects to prevent droplet aggregation. On dry basis, coconut milk consists of 5-10% protein, 80% of which are albumin and globulins. Only 30% is dissolved in aqueous phase, and the undissolved proteins act as emulsifying agents closely associated with oil globules. pH, ionic strength and temperature affects the emulsifying properties of coconut protein. Coconut protein is ineffective at creating small droplets within the homogenizer, and preventing oil droplet aggregation during or after homogenization. As such, coconut protein can only help to stabilize the oil-in-water emulsion to a certain extent. This is why when left to stand, the physical separation of coconut milk into oil-rich and water-rich layers cannot be avoided. This is also true during processing and storage. As such, emulsifier or stabilizers, coupled with the use of homogenization, can help retard coconut milk’s instability, prolonging its shelf life. FACTORS AFFECTING PROTEIN INTERACTIONS • Due to a loss of electrostatic repulsion between droplets, protein is generally poorly soluble at pH values close to their isoelectric point (pH 3.5-4) • Coconut albumin and globulins appear to be most stable over pH 5-9 • Coconut protein denature and coagulate when heated to 80°C
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EFFECTS OF ENVIRONMENTAL FACTORS AND ADDITIVES ON QUALITY HARVESTING AND PRE-TREATMENT OF COCONUT KERNEL For maximum yield of coconut milk, the nut should be 10-13 months mature, as oil content is at its highest. After the coconut is dehusked, deshelled and pared (optional), cleaning is done to minimize microbiological degradation. Coconut kernels are washed with diluted anti-microbial solutions and rinsed with potable water. HOMOGENIZATION Homogenization is a means of stabilizing the coconut milk oil-inwater against gravity separation into two phases – a water-rich bottom and fat-rich top. It causes the disruption of oil globules into much smaller ones (Figure 8.6) and also separates the globules that are attached together (Figure 8.7).
In addition, homogenization is carried out at slightly elevated temperatures with liquid coconut oil. It is ineffective when cold coconut milk is used, because coconut oil is solidified.
Figure 8.6 Disruption of fat globules in the first stage of homogenization1
Figure 8.7 Disruption of fat globules in the second stage of homogenization1
Normally, this is coupled with emulsifiers that serve as surfactants that keep the globules apart. Sometimes, homogenization is also coupled with stabilizers. This increases the viscosity of coconut milk to hold the oil globules within its colloidal network. OXYGEN Oxygen exposure can lead to the rancidity of coconut milk. This is accelerated by microbiological degradation, or the enzyme called lipase. As such, it is important to minimize oxygen exposure to prevent rancidity.
1
Figures 8.6 and 8.7 © Tetra Pak International S.A., Dairy Processing Handbook 2015
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ADDITIVES Adding stabilizers and emulsifiers To prevent instability in coconut milk, stabilizers can be used to retard phase separation during prolonged standing. It can also thicken at the continuous phase. Alternatively, emulsifiers can be added to absorb at the oil interface. Antioxidants Antioxidants are added to extend the shelf life of coconut milk products. This is done by scavenging oxygen or free radicals which minimize browning reactions or lipid oxidation. In particular, sodium metabisulphite is commonly used to help retard the non-enzymatic browning of coconut milk.
MICROBIOLOGY OF COCONUT MILK Like coconut water, coconut milk is also prone to microbiological damage. Water activity, pH, temperature, oxygen availability, and light affects the growth rate of microorganisms. In particular, water activity is defined as the ratio of water vapour pressure in food to that of pure water, at the same temperature. When a solution becomes more concentrated, vapour pressure decreases. Water activity also drops from a maximum value of one for pure water. The following systems are the major ones concerned with coconut milk and its products. BREAKDOWN OF CARBOHYDRATES The breakdown of carbohydrates in coconut milk results in the production of lactic and acetic acids leading to a drop in the pH levels. This is especially so through fermentation pathways (Table 8.3). As a result, a sour taste develops in coconut milk. CONDITION Presence of oxygen Absence of oxygen - Alcoholic fermentation - Butyric acid fermentation - Lactic acid fermentation i) Homofermentative ii) Heterofermentative
PRODUCTS CO2 + water + energy Ethanol + CO2 Butyric acid + CO2 +H2 Lactic Acid Lactic acid + ethanol + acetic acid + CO2
Table 8.3 Microbiological carbohydrate metabolism products Source: © Tetra Pak International S.A., Dairy Processing Handbook 2015
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BREAKDOWN OF OILS According to the Codex definition (CODEX STAN 240-2003), coconut milk and cream must contain at least 10% and 20% oil content respectively. With such a significant proportion of oil, it is very important to minimize microbial damage caused by lipolysis, also known as oil breakdown (Figure 8.9). As a result, rancidity occurs, which give rise to an off-flavour formation.
Figure 8.9 Lipid is broken down to free fatty acids and glyverol by the lipase enzyme1
While pure oil cannot be broken down by microorganisms, oil in water emulsions or in contact with water can be easily broken down by microorganisms (Figure 8.10). This is because water is essential for microbial enzymatic split. Figure 8.10 When fat globule membranes are damaged, lipolysis can release fatty acids
BREAKDOWN OF PROTEIN Protein denaturation is affected by the pH level of the system. The pH drop is caused by a breakdown of carbohydrates into acids. When the pH approaches the isoelectric point of the protein, it curdles as they lose their repulsive charges. The breakdown of protein, otherwise known as proteolysis in coconut milk, can also be catalysed by proteases produced by microorganisms (Figure 8.8). Proteins and their constituent amino acids have a wide combination of chemical elements. They contain carbon, hydrogen, oxygen, sulphur, nitrogen, and phosphorus. As a result, there is a much larger range of acids, alcohols, gases (hydrogen, carbon dioxide, hydrogen sulphide and ammonia) and other compounds.
Figure 8.8 Protein is broken down to amino acid by the enzymes protease and peptidase1
1
Figures 8.8-8.10 © Tetra Pak International S.A., Dairy Processing Handbook 2015
CHAPTER 9 RECOMBINED COCONUT BEVERAGES
Recombination is a good method for supplying a close alternative to fresh coconut beverages by combining the coconut with water and other ingredients. Over the years, recombination processes have been refined to become more efficient and sophisticated high capacity systems.
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RECOMBINED COCONUT BEVERAGES Recombination is a good method for supplying a close alternative to fresh coconut beverages by combining the coconut with water and other ingredients. Over the years, recombination processes have been refined to become more efficient and sophisticated, high capacity systems. Recombined coconut products can be supplied to markets where fresh raw material and coconut beverages are not easily supplied. For recombined coconut milk based products, a coconut milk source is the key ingredient used in recombined beverages. It can range from powders like spray-dried coconut milk powder, to bulk liquids like coconut milk or cream. In general, these products are consumed in the United States, Europe and Oceania markets as dairy alternatives. As such, extra care must be taken to ensure that other ingredients are dairy free as well. For recombined coconut water based products, coconut water concentrate is the key ingredient used in recombined beverages. Usually, coconut milk, cream and water are combined with other ingredients like juices, purees, cocoa, coffee, soymilk and more, forming endless possibilities of recombined coconut based beverages. These ingredients can vary, depending on the drinking quality and target cost of producing the final product.
CHAPTER 9 | RECOMBINED COCONUT BEVERAGES
MAJOR COMPONENTS OF COCONUT BEVERAGES The major ingredients used for recombined coconut beverages are water, additives, coconut source, fats and oils. WATER Water is the major ingredient in recombined coconut beverages. It is essential that the water component fulfils the WHO standards for drinking water. These include the sensory properties, physical, chemical and microbiological considerations of water. The following requirements for water quality are based on WHO guideline values and Tetra Pak specifications (Table 9.1). PARAMETER
RANGE
Taste
None
Smell
None
Turbidity, SiO2
Max 1 mg/L
Colour, Pt.
Max 20 mg/L
Organic matter
Very low
pH
7-8.5
Total hardness
4–7°dH
Iron, Fe
Max 0.2 mg/L
Manganese, Mn
Max 0.03-0.1 mg/L
Nitrate, NO3
Max 30 mg/L
Nitrite, NO2
Max 0.02 mg/L
Sulphate, SO4
Max 100 mg/L
Chloride, Cl
Max 50 mg/L
Aggressive carbon acid, CO2
Max 2 mg/L
Total count of bacteria
Max 100 CFU/mL
Total cound of coliform bacteria
0 per 100 mL
Ammonium, NH4
Traces
Ammonia, NH3
Max 0.5 mg/L
Phosphate, PO4
Max 0.2 mg/L
Magnesium, Mg
Max 50 mg/L
Calcium, Ca
Max 100 mg/L
Sodium, Na
Max 200 mg/L
Total solids
Max 500 mg/L
Chemical oxygen demand (COD), KMnO4
Max 20 mg/L
Copper, Cu
Max 0.05 mg/L
Zinc, Zn
Max 1.0 mg/L
Table 9.1 Water quality parameters
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ADDITIVES Additives serve several functions in recombined coconut beverages. For instance, the addition of minerals like calcium and fortification with fat- and water-soluble vitamins can improve the nutritional value of these products. In addition, dry additives like sugars, stabilizers and emulsifiers can be added directly into the mixing system for the desired mouthfeel and taste profile. COCONUT SOURCE The chosen coconut source can be dry or liquid, depending on the needs of the recombined product.
FATS AND OILS Occasionally, fats and oils are added to improve the texture and mouthfeel of the recombined coconut beverage.
Dry coconut sources, such as spray-dried coconut milk powder, makes shipping, warehousing and handling easy. It is important to get the specifications of the coconut powder used, as some of these powders are not suitable for dairy-free coconut beverages. For example, coconut powders commonly contain the milk protein casein to prevent lumping of the fats during the spray drying process. Liquid forms of concentrated coconut sources are available as coconut milk, cream or water concentrate. These can easily turn into a beverage by diluting the liquid concentrate.
Factors to consider are wettability, dispersability, solubility, dairy content and suspendability of the chosen coconut source.
Wettability The degree of wettability is very much a function of the particle volume. Agglomerated powders have improved wettability because of their increased particle size. This improves capillarity where more water is drawn into the powder particles. This causes the powders to disperse and dissolve faster in water. Dispersibility Good dispersibility is obtained when powders are distributed in water as single particles without lumps. This is determined by the structure of powder particles, as well as the configuration of protein and oil molecules. Solubility Solubility is defined by how well the powder dissolves or forms a stable suspension. For coconut milk products, this depends a great deal on how the product is being processed. Suspendability Suspendability refers to the protein source’s ability to stay in suspension. It is a function of specific volume and particle size. For beverages, maintaining the suspension of protein and fortification like calcium is important.
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RECOMBINATION TECHNOLOGY RECOMBINATION PROCESS OF COCONUT MILK BASED BEVERAGES During the recombination process, a specified amount of water is first measured and heated to a warm temperature in the tank. This allows the powder to dissolve more easily. Then, stabilizers, emulsifiers and coconut powder, milk, cream or concentrate are steadily added to the tank. Agitation is applied until all the powder is dissolved, and the resulting solution stands for a period of time. Thereafter, oil can be added into the mixture before it is reheated.
Legend: Ingredient Powder Water Fat Recombined Product Heating Medium Cooling Water Figure 9.1 Mixing tank for recombination © Tetra Pak International S.A., Dairy Processing Handbook 2015
If processing continues in the tank, the agitator is switched to high speed for some minutes to disperse the fat and oil. Next, pasteurization takes place. A homogenization step is usually incorporated in the pasteurizer to break up fat and oil globules to minimize creaming in the product. Finally, cooling to packing temperature occurs.
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In large scale production, recombination plants are built for capacities as large as 20 000 L/h. In larger plants, parallel lines are installed to meet higher capacity requirements. The production sequence in a large plant is essentially the same as in a small one, except that the larger facility requires more tanks for larger volumes of storage, melting of fats and oils, mixing, and buffer storage of the finished product. The degree of mechanisation may also differ. For instance, in large plants, weighing tanks are used to accurately measure the ingredient dosage required. On the contrary, the weighing tank can often be replaced by a dosing pump or preweighed dry ingredients in smaller plants. Large scale production In large scale production, a high-speed blender is used to mix dry ingredients first. The dry blend is then dispersed into the water through a hopper that operates at a rate of up to 45 kg per minute. When all the powder has been added, the contents of the tank are left to stand for hydration of the powders. Meanwhile, the blender is fed with the next batch of dry ingredients for recombination. If the production requires the addition of oil, it is first measured in the weighing funnel, then store in the oil storage tank before it is added into the mixture. The agitator, specially designed for optimum oil dispersion, runs for several minutes and finely disperses the oil in the coconut blend. When all the ingredients have been mixed in one tank, the process is repeated in the next tank. The coconut blend and oil mixture is drawn from the full mixing tank by a pump which moves the mixture through duplex filters. This removes foreign objects such as pieces of string or sacking. After pre-heating in the heat exchanger, the product is pumped to the homogenizer, where the dispersion of oil globules is completed. During the powder-mixing operation, it may pick up large volumes of air, which can cause fouling in the pasteurizer and homogenization problems. To eliminate this, a vacuum deaerator vessel can be installed in the production line before the homogenizer. Alternatively, a high shear vacuum mixer can be used for the recombination process. Before the product is flashed in the deaerator, it is preheated to 7–8°C above homogenization temperature, with the vacuum adjusted so that the outgoing product has the correct homogenization temperature. Next, the homogenized coconut beverage is pasteurized and chilled in the plate heat exchanger then pumped to storage tanks for further processing or directed to packaging.
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For further processing, three methods are commonly used – pasteurization, in-container sterilization of coconut beverages and UHT treatment by direct or indirect heating. As such, the design of the plant is influenced not only by its capacity, but also by the recombination process. In smaller plants where the mixing of material in a processing tank is limited, the product will be naturally and satisfactorily deaerated if a reconstitution temperature of approximately 40°C is maintained. At this temperature, all the powder has been dissolved and the resultant solution is allowed to stand for 20 minutes with the agitator switched off. The same procedure should also be applied to large-scale production. In addition, the product is deaerated by vacuum treatment that is connected to the heating process. RECOMBINATION PROCESS OF COCONUT WATER BASED BEVERAGES In the recombination of coconut water based beverages, the process is relatively simpler than the recombination of coconut milk based beverages. However, there is a set of critical factors to take note of. Normally, coconut water concentrate between the range of 16-65 ˚Brix is used. To reconstitute coconut water, coconut water concentrate is simply blended with water. Blending is recommended to be done cold to minimize any degradation reactions, such as browning and microbiological degradation. At this stage, other ingredients like juices and additives are also added. After mixing, the beverage is immediately fed to the heat exchanger for pasteurization, deaeration and chilling. It is then pumped to storage tanks for further processing (UHT) or direct to packaging. For further processing, three methods are commonly used – pasteurization, in-container sterilization of coconut beverages and UHT treatment by direct or indirect heating. As such, the design of the plant is influenced not only by its capacity, but also by the recombination process.
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HANDLING COCONUT BEVERAGES When handling recombined coconut beverages, it is necessary to ensure that the products reach consumers in mint condition. Firstly, the products should be packed as soon as possible after production. UHT treated coconut beverages must flow in a closed aseptic system to the aseptic carton or can filling machine. Pasteurized coconut beverages can be packed in paper-based laminates, plastic packs or glass bottles. For long life products, the package must always be airtight to protect the coconut beverages from oxidation. It should also be strong enough for stacking in crates or boxes. A buffer tank may be needed to compensate for temporary stoppages in the production or packing lines. In the case of sterilized coconut beverages, this tank must be of aseptic design to prevent reinfection. After packing sterile coconut beverages, they can be stored in any condition, provided that the packages are intact. Pasteurized coconut beverages must be kept in cold storage rooms, while UHT treated and sterilized coconut beverages can stand without a refrigeration chain. This is because the latter are much more tolerant of ambient temperature and other conditions than pasteurized coconut beverages. Last but not least, recombined coconut beverages are transported for market distribution. For UHT treated coconut beverages, the time factor is not too important as they can be transported over long distances and displayed for sale without refrigeration. On the other hand, when pasteurized coconut beverages are transported from place to place, they require a refrigeration chain of insulated distribution vans, chilled counters in the shops, and preferably, home refrigerators.
CHAPTER 10 RHEOLOGY
Rheology is one of the most important considerations in designing food processing plants for clarified liquid coconut milk extract. It is defined as the science of dealing with flow, and the deformations that result from flow.
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RHEOLOGY Rheology is one of the most important considerations in designing food processing plants for clarified liquid coconut milk extract. It is defined as the science of dealing with flow, and the deformations that result from flow. Specifically, the deformation of flow involves viscosity – the internal friction which occurs when a layer of fluid is made to move against another layer of fluid.
SHEARING In rheology, shearing is the key to understanding flow behaviour and structure. Shearing between parallel planes is normally used for the basic definition of shear stress and rate, depending on how much and how quickly the deformation is applied to the material (Figure 10.1).
Figure 10.1 Definition of shear stress and shear rate is based on shearing between parallel planes
To derive viscosity, shearing must induce the stationary flow of substance. This is achieved by rearranging and deforming particles, breaking the bonds in the structure of the material. For further analysis, shearing is done gently to prevent the structure from destruction. To do so, an oscillating shear, with amplitude low enough to study an unbroken structure, is applied to the material.
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A sheared flow occurs between parallel planes. Other flows include a rotational flow between stationary and rotating coaxial cylinders; a telescopic flow through capillaries and pipes and a torsional flow between parallel planes (Figure 10.2).
Figure 10.2 Different types of shearing
Shear stress (σy/x) is defined as σy/x = F/A [Pa]
Shear rate (γ) as γ = dγ/dt = dv/dγ [1/s]
WHERE F = force, N A = area, m2
Apparent viscosity (ηa) as ηa = σ/γ [Pa.s]
TYPES OF VISCOSITY TYPE
DESCRIPTION
Absolute
Absolute viscosity is the viscosity measured by any system geometry not under the influence of gravity to obtain measurements.
Kinematic
Kinematic viscosity is the viscosity measured by any system geometry that utilizes gravity to obtain measurements.
Apparent
Apparent viscosity is the viscosity of a non-Newtonian liquid, or the viscosity that is measured at a single shear rate or single point.
Table 10.1 Types of viscosity
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The direct proportionality between shear stress and rate in laminar flow is specified by
σyx = η • dv/dy = η • γ
TYPES OF FLOW Depending on the material’s flow behaviour, viscosity is classified as Newtonian or non-Newtonian. Newtonian flow is characterized by viscosity that is independent of the shear rate at which it is measured. There is a constant viscosity dependent on temperature, but independent of the applied shear rate. The proportionality constant is equal to the viscosity of the material. The flow curve, which plots shear stress against shear rate, is a straight line with slope η for a Newtonian fluid (Figure 10.3). On the other hand, the viscosity curve, which plots viscosity against shear rate, will show a straight line at a constant value equal to η (Figure 10.4).
Figure 10.3 Flow curves of Newtonian and nonNewtonian fluids
Examples of Newtonian fluids are water, mineral oils, liquid lecithin, prune concentrate, various syrups, and fructose in water, cottonseed oil, wine and pure sucrose solutions. It also includes low concentration liquids in general, such as whole milk and skim milk. Non-Newtonian flow is used to describe materials which cannot be defined by a single viscosity value at a specified temperature. As such, the viscosity of these materials must always be stated together with its corresponding temperature and shear rate. If the shear rate is changed, the viscosity will also change. In general, high concentration and low temperature may induce or increase nonNewtonian behaviour.
Figure 10.4 Viscosity curves for Newtonian and nonNewtonian fluids
Besides the magnitude of the shear rate, the viscosity of non-Newtonian fluids may also be time dependent. In most cases, the frequency of successive applications of shear also determines viscosity. Examples of non-Newtonian materials which are dependent on time are yogurt and mayonnaise. Non-Newtonian materials can also be independent of time. Examples are tomato ketchup and coconut milk. For time-independent Non-Newtonian materials, flow behaviour can be classified as shear-thinning, shear-thickening and plastic. While materials that are time dependent are defined as thixotropic, rheopectic or anti-thixotropic.
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107 Characterization of rheological properties in foods is important. It ensures the proper sterilization of the slowest heating element in aseptic processing design, which strongly affects the change in the flow region of non-Newtonian liquid foods. As such, the flow behaviour of liquid foods has an important role in the residence time distribution and heat transfer rate in aseptic processing design.
Typical examples of shear thinning fluids are creams, juice concentrates and salad dressings.
SHEAR-THINNING FLOW BEHAVIOUR Shear thinning flow behaviour is mainly caused by the increased shear rate deforming and/or re-arranging particles, resulting in lower flow resistance and subsequently, lower viscosity. The viscosity of a shear thinning or pseudo-plastic fluid decreases as shear rate increases. While many liquid food systems belong to this category of fluids, the shear rate dependency of viscosity can vary depending on the type of products, temperatures and concentrations of a given liquid. For coconut milk, studies have shown that it exhibits shear thinning behaviour over 15-30% oil concentrations when mixed with emulsifiers, pre-heated and homogenized (Tipvarakarnkoon, 2009).
A typical example of shear thickening systems is concentrated starch suspensions.
SHEAR-THICKENING FLOW BEHAVIOUR A shear thickening fluid usually exhibits dilatant flow behaviour. This is generally found among very high concentration suspensions. The viscosity of a shear thickening fluid increases as shear rate increases. The solvent acts as a lubricant between suspended particles at low shear rates, but is squeezed out at higher shear rates, resulting in denser packing of particles. PLASTIC FLOW BEHAVIOUR A plastic fluid exhibits yield stress. The result is that a significant force must be applied before the material starts to flow like a liquid, which is often referred to as the ketchup effect. If the force applied is smaller than the yield stress, the material stores the deformation energy and exhibits elastic properties while behaving like a solid. The liquid starts to flow like a Newtonian liquid when yield stress is exceeded. Otherwise known as a Bingham plastic liquid, it can also flow like a shear thinning, visco-plastic liquid. Typical plastic fluids are quark, tomato paste, certain ketchups and greases. For time-dependent Non-Newtonian materials, flow behaviour can be classified as thixotropic, anti-thixotropic and rheopectic. Thixotropic flow behaviour is normally studied in a loop test when the material is subjected to increasing shear rates, followed by the same shear rates in decreasing order. A thixotropic fluid is a shear thinning system where viscosity decreases with a constantly increasing shear rate. It also decreases with time at a constant shear rate.
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Time-dependent thixotropic flow behaviour is observed from the difference between ascending and descending viscosity and shear stress curves (Figure 10.5).
Figure 10.5 Flow curves for time-dependent non-Newtonian fluids
To recover its structure, the material must rest for a certain period of time, which is characteristic of those included in gel-forming systems. Typical examples are yoghurt, mayonnaise, margarine, ice cream and brush paint. RHEOPECTIC FLOW BEHAVIOUR A rheopectic fluid is a thixotropic fluid with a structure that only recovers completely if subjected to a small shear rate. This means that a rheopectic fluid will not rebuild its structure at rest. ANTI-THIXOTROPIC FLOW BEHAVIOUR Anti-thixotropic flow behaviour is also illustrated by a loop test, and is very uncommon among foodstuffs. This is because anti-thixotropic fluids have a shear thickening system where viscosity increases not only with increasing shear rate, but also with time at a constant shear rate. Several models are available to mathematically describe the flow behaviour of non-Newtonian systems. Examples are Ostwald, Herschel-Bulkley, Steiger-Ory, Bingham, Ellis and Eyring. These models relate the shear stress of a fluid to the shear rate. As always, the apparent viscosity is calculated as the variable between shear stress and shear rate.
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FLOW BEHAVIOUR MODELS POWER LAW EQUATION The most general flow behaviour model is the Herschel-Bulkley model, also known as the power law equation. In principle, it is an extended Ostwald model. This equation is applicable to a great number of non-Newtonian fluids over a wide range of shear rates. It is also applicable to plastic, shear thinning and shear thickening fluids according to
WHERE
(σ-σ0) = K • γn
σ = shear stress, Pa σ0 = yield stress, Pa K = consistency coefficient, Pas.n γ = shear rate, s-1 n = flow behaviour index, dimensionless
The power law equation also lends itself readily to calculating pressure drop and heat transfer. Thus, it is the most appropriate rheological model for clarified liquid coconut milk extract. The apparent viscosity of clarified liquid coconut milk extract decreases when temperature increases. When concentration of clarified liquid coconut milk extract increased, the apparent viscosity also increased (Simuang et al., 2004). Appropriate modifications of the generalized power law equation makes it possible to express each type of flow behaviour. For Newtonian fluids, the power law equation, given K = η and n = 1, is specified as
σ = K • γn = η • γ For a plastic fluid, the power law equation is used in the fully generalized form, with n<1 for visco-plastic behaviour and n = 1 for Bingham plastic behaviour. For a shear thinning or shear thickening fluid the power law equation is specified as
σ = K • γn
(with n<1 and n>1, respectively)
For thixotropic fluids, mathematical models that are more complex than the models discussed so far are required. Thus, they are described by time-independent process viscosities normally fitted to the power law equation.
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TAKING VISCOSITY MEASUREMENTS The unit of viscosity is Pas (Pascal second), which is equal to 1000 mPas or 1000 cP (centipoise).
Viscosity measurements are used extensively in the food industry. It allows technologists to control the quality of raw materials when assessing the effects of changes in formulation, as well as the effect which processing conditions have on products and their development. When obtained from in-line systems or batch sample tests, viscosity measurements will help reduce ingredient costs and ensure batch-to-batch product consistency. General guidelines to taking viscosity measurements are at the end of this page. The measuring equipment used is the viscometer. Two main types are rotational and capillary. Compared to capillary viscometers, rotational viscometers are more flexible and easier to use. On the other hand, at low viscosities and high shear rates, capillary viscometers have more accurate measurements than rotational viscometers.
With technology advancements, portable viscometers also come with
Rotational viscometers are available as portable and stationary instruments. Portable types are operated manually, and usually come in a shock proof case equipped with all necessary accessories.
software to allow model fittings to data and provide connections with personal computers. This allows for almost the same measurement
Usually, stationary installations automate measuring sequences and data evaluation with computer controls. The software includes possible fitting to a number of rheological models, plotting of flow curves and more.
types as stationary viscometers.
Normally, a rotational viscometer is insufficient for a complete rheological analysis, which includes determining the structure breakdown in for instance, coconut milk yoghurt. For such analysis, a more sophisticated instrument called a rheometer is used. It operates with torsional vibration or oscillation rather than rotation. The fluid is also rheologically analysed without destroying its structure.
GUIDELINES TO TAKING VISCOSITY MEASUREMENTS 1. The temperature is kept constant during the test period for accurate measurement. - A temperature change of 3ºC can cause at least 10% change in viscosity. - As some products are more temperature sensitive than others, it is even more crucial to keep the temperature constant. 2. To further increase the accuracy of data evaluation, measurements should be made at as many different shear rates and temperatures as possible. 3. When utilizing different temperatures, heating effects must also be considered. For example, the viscosities of warm swelling starch differs significantly before and after heating. 4. Other factors include storage and time. For example, if the purpose is to supply data for process design, the measurements should be made as near to the actual processing stage as possible. 5. Proper instrumentation and experimental procedure should also be established.
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VISCOSITY IN COCONUT MILK Viscosity in coconut milk is affected by added ingredients. For example, different manufacturers add different ingredients like starches, stabilizers and emulsifiers to coconut milk. As such, the viscosity data can vary widely among fluid foodstuffs. In particular, studies have shown that coconut milk, mixed with emulsifiers and subsequently pre-heated or homogenized exhibit pseudo-plastic, shear thinning behaviour over a 15-30% range of oil content (Tipvarakarnkoon, 2009). Viscosity of coconut milk is also affected by oil content, heat and homogenization (Table 10.2). Often, emulsifiers are added to homogenize coconut milk and extend the product’s shelf life. FACTORS
DESCRIPTION
Oil content
Viscosity increases as oil content increases from 15-30%. At higher fat concentrations, the presence of a large number of fat globules increases the resistance to flow which, in turn, increases the apparent viscosity of the emulsion system (Simuang et al., 2003).
Homogenization and Emulsification of oil globules
Efficient homogenization increases viscosity of coconut milk. It is typically used in combination with emulsifiers or stabilizers to increase the emulsion stability, which minimizes creaming. When coconut milk is homogenized, oil globules increase in numbers and become smaller. They have to be kept apart by coconut protein, emulsifiers and stabilizers, which act as surfactants or create a fluid gel network. This prevents flocculation and coalescence, which minimizes creaming. After homogenization, particle-particle interaction like oil interface with protein or emulsifiers increases. As a result, the resistance to the flow of coconut milk also increases.
Heat
Heat affects the fluidity of the oil content. For efficient homogenization to increase coconut emulsion stability, the oil has to be in liquid form. If the oil is in solid form, homogenization will be inefficient. Heat also affects coconut protein stability. At high temperatures, some heat labile coconut protein molecule can undergo denaturation and are unable to act as surfactants at the oil-water interface of the emulsion. This results in flocculation, where small oil globules form irregular arrangements of aggregates. Flocculation results in a lesser number of suspended single oil globules to resist flow, thereby causing a reduction in viscosity of coconut milk (Chiewchan et al., 2005).
Table 10.2 Factors affecting the viscosity of coconut milk
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Analysis of commercial samples at Tetra Pak’s in-house rheology lab (RheoLab) shows that, at a shear rate of 100s-1 between oil content of 17-25.1% at 30°C, the viscosity of coconut milk can range from as low as 8 mPas to as high as 260 mPas. Increasing homogenization pressures can also increase viscosity. At higher pressures, the oil globules are broken into smaller and more numerous numbers, thereby increasing viscosity (Table 10.3).
HOMOGENIZATION HOMOGENIZATION PRESSURE (mPa) PRESSURE (bar)
APPARENT VISCOSITY (mPa.s) AT SHEAR RATE OF 300s-1, 30°C
0
0
15.4
15
150
27.1
18
180
28.0
21
210
31.0
24
240
35.5
27
270
45.5
Table 10.3 Apparent viscosity of 35-37% oil content in coconut milk at increasing homogenization pressures Source: Chiewchan et al., 2005
Our RheoLab in Sweden is also equipped with stationary and portable viscometers for measurements at customer sites. Viscosity can be measured between 5-140°C, while samples can be stored and shipped at temperature conditions agreed with the customer. If certain specific analyses are requested, Tetra Pak can in most cases organize them at an external laboratory, as we have a network of institutes for food analysis and sensory evaluations.
CHAPTER 11
LONG LIFE COCONUT LIQUID PRODUCTS Long life coconut liquid products are coconut liquid products sterilized by undergoing strong heat treatment to inactivate microorganisms and heat resistant enzymes. As such, they can be stored for long periods of time at ambient temperatures without bacterial growth.
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LONG LIFE COCONUT LIQUID PRODUCTS PROCESSING LONG LIFE COCONUT LIQUID PRODUCTS Long life coconut liquid products are coconut liquid products like coconut milk based or coconut water based beverages, coconut milk or cream sterilized by undergoing strong heat treatment to inactivate microorganisms and heat resistant enzymes. As such, they can be stored for long periods of time at ambient temperatures without bacterial growth. Properly processed coconut products are safe and hygienic. Consumers benefit from a product that can be stored for long periods of time without refrigeration. It can also be distributed over long distances and supplied to new markets. Essentially, there are three heating processes for extending the shelf life of coconut liquid products – pasteurization, sterilization and ultra-high temperature processing. Each process requires specific types of packaging in order to maximize its effect (Table 11.1). The exact shelf life of coconut liquid products depends on the raw materials, processing conditions and type of packaging used.
TREATMENT TEMPERATURE Pasteurization
In-container sterilization
UHT
TIME
PACKAGE
SHELF LIFE1
75-85°C
15-120 seconds
Plastic bags, Paper cartons, Glass bottles
1 week, Refrigerated
121°C
20-30 minutes
Cans, Retort pouches, Glass bottles
2 years, Nonrefrigerated
137-145°C
4-15 seconds
Aseptic packages e.g. paper cartons
6-8 months, Nonrefrigerated
Table 11.1 Heat treatment and package considerations for coconut beverages and coconut milk 1 Assumption: Shelf life refers to the “best before” date or predating of the product. Note: Shelf life is subjected to different products, heat and storage conditions, as well as the type of packaging used
MICROBIAL LOAD OF RAW MATERIAL Coconuts have a high microbial load, especially those left on the ground after harvesting and transported over long distances. In particular, dehusked mature coconuts contain higher microbial load as the fibres tend to trap soil and dirt. To reduce microbial load, it is recommended that coconut processing includes a cleaning stage during production.
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Cleaning efforts vary for young and mature coconuts. For young coconuts, the whole fruit is brushed and washed in potable water to remove soil and dirt. Sanitizing the fruit in a dilute bleach solution further reduces the number of microorganisms on the surface of the young coconut. (FAO,2007) To reduce microbial load for mature coconuts, they are deshelled and pared down before the white or brown skin kernels are washed. The pieces of coconut kernels are washed with diluted anti-microbial solutions, followed by rinsing with potable water before going into the grinders for coconut milk extraction.
STERILIZING EFFECT ON COCONUT LIQUID PRODUCTS When microorganisms and bacterial spores are subjected to heat treatment or any other kind of sterilizing procedure, not all are killed at once. Instead, a certain proportion is destroyed in the given time period, while the remaining portion survives. If the surviving microorganisms are subjected to the same treatment again over the given time period, the same proportion will be destroyed and so on. In other words, a given exposure to sterilizing or disinfectant agents always kills the same proportion of microorganisms present. LOGARITHMIC DEATH RATES OF SPORES Microorganisms are reduced in a semi-logarithmic fashion when exposed to a lethal effect. As such, the logarithmic function can never reach zero. Sterility, which implies the total absence of all living microorganisms, is therefore impossible. In reality, “sterilizing effect” or “sterilizing efficiency” are more apt descriptions for the number of decimal reductions in counts of bacterial spores achieved by a sterilization process. When a sterilization process is performed every time, it can be characterized by a certain sterilizing effect. An effect factor of 9 here indicates that out of 109 bacterial spores fed into the process, only 1 (100) will survive (Figure 11.1). EFFECT FACTOR 9 109 Bacterial Spores Figure 11.1 Sterilizing effect of 9
UHT
100 = 1
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The sterilizing effect is independent of the volume and number of microorganisms (spores). The function is:
WHERE
K x t = log N/Nt
K = a constant t = time of treatment N = number of microorganisms (spores) originally present Nt = number of microorganisms (spores) present after a given time of treatment
STERILIZING EFFECT ACHIEVED THROUGH UHT In general, the sterilizing effect depends on the time and temperature combination, as well as the product’s bacteria content. Bacteria content exists as easy to kill vegetative cells only, or as spore-forming bacteria in a vegetative state. While these bacteria are easily killed in the vegetative state, their spores are difficult to eliminate. In turn, the heat resistance of the test spores are influenced by the Bacillus strain used, which affects the way spores are produced. Spores of Bacillus subtilis or Bacillus stearothermophilus are generally used as test organisms to determine the sterilizing effect of UHT equipment, especially when strains like B.stearothermophilus form fairly heat-resistant spores. Clostridium botulinum is used to determine the effect of in-container sterilization. Products to be sterilized usually contain a mixed flora of both vegetative cells and bacterial spores. Unfortunately, high spore counts can be found in products with low total counts, and vice versa. Therefore, the total count determination cannot serve as a reliable base for enumeration of spores in food products. To determine this, Q10 and F0 values serve as a base for the killing of microorganisms.
The Q10 value for all flavour and most chemical changes is between 2-3.
Q10 value Ranging from 8-30, Q10 values can be used to determine the killing of bacterial spores. The range widely varies because different bacteria spores react differently to temperature increases. Q10 values state how many times the speed of a reaction increases if the temperature of the system is raised by 10°C. This is due to the sterilizing effect of a heat process that increases rapidly with rising temperature, which is consistent with the chemical reactions that occur as a consequence of heat treatment.
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F0 value F0 value expresses the relationship between time and temperature of sterilization, where the F-value for a process is the number of minutes required to kill a known population of microorganisms in a given amount of food under specified conditions. The F0 value is based on a z-value of 10°C and states the minutes required at a temperature of 121.1°C to achieve a sterilizing effect of 12D.
WHERE
t F0 = x 10 60
T-121.1ºC z
t = sterilization time in seconds at temperature T in ˚C T = sterilization temperature in ˚C z = a value expressing the increase in temperature to obtain the same lethal effect in one-tenth of the time
The value varies with the origin of the spores (10-10.8°C) and can generally be set as 10°C. D-value Decimal reduction time (D-value) is defined as the time required at any given temperature for a 90% reduction (= 1 log value) in viability of microorganism to be effected. z-value z-value is defined as the temperature increase required to increase the death rate by tenfold. In other words, it is the temperature required to reduce the D value by tenfold (Figure 11.1). Figure 11.1 The z-value expresses the increase in temperature to obtain the same lethal effect in a tenth of the time
CHEMICAL AND BACTERIOLOGICAL CHANGES WITH HIGH HEAT TREATMENT During coconut beverage processing, high heat treatment causes multiple chemical and bacteriological changes. It destroys most microorganisms present in the coconut liquid extract, and increases the shelf life of the coconut beverage. It is important to remove all microorganisms during heat sterilization. Due to the effectiveness of sterilization, vegetative organisms present in coconut liquid products are more easily killed. On the other hand, resistant spores are more likely to survive as compared to vegetative organisms in some sterilization processes. Resistant spores may survive thermal treatments of temperature and time settings of up to 100°C for 30 minutes. Although high heat treatment has many benefits, extended heating should be avoided as it leads to the destruction of nutrients, such as essential amino acids and vitamins. It also causes Maillard browning and develops a cooked flavour.
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When heat treatment is applied to coconut products, it is important to ensure optimum conditions for sterilizing effectiveness. These include temperature, time, moisture content and pressure to maximize the destruction of microbial spoilage agents, while minimizing the unwanted effects of heat. The changes in chemical properties and spore destruction are shown in Figure 11.2. It can be seen that in the range of UHT temperatures, the bacteriological killing effect increases considerably with temperature, whereas the chemical changes remain mild. This clearly illustrates the advantages of UHT treatment against in-container sterilization operating at low temperatures for a long time (Figure 11.3). Ultra high temperatures with short holding times (Figure 11.4) can provide a high sterilization effect while causing only minimal chemical changes in the treated product. In-container sterilization operating at low temperatures for a long time leads to more extensive changes in product quality.
Figure 11.2 Curves representing the speed of changes in chemical properties and of spore destructure with increasing temparature1
Figure 11.3 Temperature curve for in-container sterilization1 1
Figures 11.2-11.4 © Tetra Pak International S.A., Dairy Processing Handbook 2015
Figure 11.4 Temperature curves for direct, A, and indirect, B, UHT treatment1
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SHELF LIFE For long life products, shelf life is defined as the time the product can be stored before its quality falls below an acceptable, minimum level. This is determined by the product taste, colour, smell, jellification, sedimentation, fat separation and viscosity. During storage, the sensory properties of coconut beverages can deteriorate. For coconut water, colour may change from colourless to brown or pink, while turbidity may increase due to flocculation. For coconut milk and its products, separation between oil and aqueous phases may occur, which also affects the viscosity properties. Factors affecting the shelf life of coconut liquid products are shown in Figure 11.5.
1
Raw product quality
2
Operation and hygiene
3
Processing and storage conditions
4
Packaging machine system
5
Packaging configuration and seal quality
6
Distribution conditions and temperature
7
Consumer handling
Figure 11.5 Factors affecting shelf life of coconut liquid products
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PRODUCING LONG LIFE COCONUT LIQUID PRODUCTS There are two methods used for the production of long life coconut beverages – in-container sterilization and Ultra High Temperature (UHT) treatment. IN-CONTAINER STERILIZATION There are two processes used for sterilization in bottles or cans – batch processing in autoclaves and continuous processing, using systems such as vertical hydrostatic towers and horizontal sterilizers. Batch processing Batch processing can be operated by three methods:
1
In stacks of crates in a static pressure vessel (Figure 11.6)
2
In a cage which can be rotated in a static autoclave
3
In a rotary autoclave
Figure 11.6 Batch processing in a static pressure vessel1 © Tetra Pak International S.A., Dairy Processing Handbook 2015
In a rotary autoclave, it has an advantage over the static methods due to a quicker uptake of heat from the heating medium, as well as greater uniformity of treatment for killing bacteria and ensuring colour uniformity. By batch processing in autoclaves, the product is usually preheated, then transferred into clean, heated bottles. As such, heat resistant packaging materials must be used. The bottles are then capped, placed in a steam chamber and sterilized. Later, the batch is cooled, and the autoclave is filled with a new batch. Since sterilization takes place after bottling or canning, this eliminates the need for aseptic handling. However, heat resistant packaging materials must be used.
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Continuous processing Continuous processing systems are normally preferred when more than ten thousand units per day are produced. For the smooth running of operations, the design of such machines depends on the use of a pressure lock system through which the filled containers pass from low pressure, low temperature conditions into a relatively high pressure, high temperature zone, after which they are subjected to steadily decreasing temperature-pressure conditions, and are eventually cooled with chilled or cold water. There are two main types of machines available for continuous sterilization, depending on the type of pressure lock system used. The hydrostatic vertical bottle sterilizer 1
First heating stage
2
Water seal and second heating stage
3
Third heating stage
4
Sterilization section
5
First cooling stage
6
Second cooling stage
7
Third cooling stage
8
Forth cooling stage
9
Final cooling stage
10
Upper shafts and wheels, individually driven
Legend: Product Steam Cooling Water Figure 11.7 Hydrostatic vertical continuous bottle sterilizer © Tetra Pak International S.A., Dairy Processing Handbook 2015
Often referred to as the tower sterilizer, the hydrostatic vertical bottle sterilizer consists of a central chamber maintained at a sterilizing temperature by steam under pressure, while counterbalanced by the equivalent pressure of water columns.
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Water is heated on the inlet side and cooled on the outlet side, while temperatures are adjusted to give maximum heat uptake and abstraction. At the same time, breakage of glass packaging is avoided by thermal shock. In the hydrostatic tower, the filled containers are slowly conveyed through successive heating and cooling zones. These zones are sized to correspond with the required temperatures and holding times at various treatment stages. The horizontal rotary valve-sealed sterilizer
1
Automatic loading of bottles or cans
2
Rotating valve simultaneously transport bottles into and out of pressure chamber
3
Sterilization area
4
Ventilation fan
5
Pre-cooling area
6
Final cooling at atmospheric pressure
7
Unloading from conveyor chain
Legend: Product Steam Cooling Water
Figure 11.8 Horizontal sterilizer with rotary valve seal and positive pressurisation (steam/air mixture) facility © Tetra Pak International S.A., Dairy Processing Handbook 2015
The rotary valve sealed sterilizer is a comparatively simple machine with a mechanically driven valve rotor. The filled containers are conveyed into a relatively high pressure, high temperature zone where they are subjected to sterilizing temperatures. The rotary valve sealed sterilizer can be used for the sterilization of plastic and glass bottles, as well as flexible containers of plastic film and laminates. ULTRA HIGH TEMPERATURE (UHT) TREATMENT Ultra High Temperature (UHT) is a technique used for preserving liquid food products by exposing them to brief, intensive heating. This treatment destroys the microorganisms in the product with a continuous inflow process. It is based on the rapid heating of the product to the required sterilization temperature, followed by a short period of holding time at that temperature and rapid cooling. The purpose of UHT treatment is to achieve commercial sterility of the product.
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UHT treatment conditions vary from product to product, depending on the raw materials used and its microbial load. As such, different coconut liquid products require different UHT treatments. For example, coconut water is generally more sensitive to heat, as compared to coconut milk. Coconut milk requires higher thermal impact to achieve commercial sterility as it contains fibres and is higher in viscosity (Table 11.2). In another example, when dairy milk or soya powder is added to coconut water, a higher temperature is recommended. If the microbial load is too high for the UHT treatment to handle, the coconut liquid products can be subjected to an upstream step of pasteurization to lower the microbial load before UHT handles the remaining microorganisms. Additionally, some countries impose food regulations which have a requirement for UHT treatment of coconut products. For instance, long life coconut liquid products in the USA have to undergo UHT equivalent to F0 of 5 > at 121°C = 5 minutes. PRODUCT
pH
HEATING TEMPERATURE
HOLDING TIME
Low acid coconut water or milk based beverages
>4.6
137-145°C
4-15 seconds
High acid coconut water or milk based beverages
<4.6
110-125°C
15-30 seconds
Coconut milk
>4.6
140-145°C
8-15 seconds
Table 11.2 UHT conditions for coconut liquid products
In UHT treatments, the product is first heated before aseptic packaging, which protects the product against light and atmospheric oxygen. This only applies when the product remains under aseptic conditions, so it is necessary to prevent re-infection by packaging the product in previously sterilized packaging materials after heat treatment. Any intermediate storage between treatment and packaging must take place under aseptic conditions. This is why UHT processing is also called aseptic processing.
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Indirect UHT system
1
Balance tank
2
Feed pump
3
Plate heat exchanger
4
Non-aseptic homogenizer
5
Holding tube
6
Aseptic tank
7
Aseptic filling
8
CIP Legend: Product
Hot Water
Steam
Diverted Flow Product
Cooling Water Figure 11.9 UHT process with heating by indirect heating in plate heat exchanger1
With indirect UHT systems (Figures 11.9 and 11.10), a heat exchange surface separates the product from the heating or cooling media. The heating medium can be either steam or water in a plate or tubular heat exchanger (see Figures 11.11, 11.12, 11.13 and 11.14). Typically, the product enters the sterilizer via a balance inlet tank and a centrifugal feeding pump at 4-25ºC. Subsequently, it is heated to 70-75ºC when the product is homogenized. 1
Balance tank
2
Feed pump
3
Tubular heat exchanger, regenerative preheater and cooler
4
Non-aseptic homogenizer
5
Tubular heat exchanger, heater
6
Tubular heat exchanger, final heater
7
Tubular heat exchanger, cooler
8
Aseptic tank
9
Aseptic filling
10
CIP
Legend: Product
Hot Water
Steam
Diverted Flow Product
Cooling Water Figure 11.10 Indirect UHT system based on tubular heat exchangers1
1
Figures 11.9-11.14 © Tetra Pak International S.A., Dairy Processing Handbook 2015
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For coconut milk based liquid products, a two stage homogenization of total pressure ranging from 150-200 bar is often used. The product is then pushed through the remaining equipment for sterilization. Sterilization temperatures are usually 137-145ºC. Holding times between 4-15 seconds at the sterilization temperature are common. Alternatively, the coconut milk goes through sterilization first before going into an aseptic downstream homogenizer at 150-200 bar, 70-75ºC. Often, downstream (aseptic) homogenization is preferred for coconut milk, as it results in better texture and stability characteristics. The coconut milk is prone to oxidative damage. In order to lower the air content of the product, deaeration can be introduced prior to upstream homogenization. The degree of deaeration depends on the temperature and vacuum pressure applied in the deaerator. Indirect systems offer good possibilities for regenerative energy recovery, as the incoming product is heated by the outgoing beverage. For both plate and tubular (single and multiple tube) systems for commercial production, capacity ranges from 1,000 to 30,000 litres per hour, or even more.
Figure 11.11 Plate heat exchanger1
Figure 11.13 Tubular heat exchanger1
Figure 11.12 Flow and heat transfer in a plate heat exchanger1
Figure 11.14 Flow and heat transfer in a tubular heat exchanger1
THE ADVANTAGES OF INDIRECT UHT SYSTEMS COMPARED TO DIRECT UHT SYSTEMS
1
2
3
4
Technical simplicity
Lower investment cost
Flexibility with regards to particles
Comparatively low running costs, due to better heat recovery
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Direct UHT system 1
Balance tank product
2
Feed pump
3
Plate heat exchanger
4
Steam injection head
5
Holding tube
6
Vacuum vessel
7
Vacuum pump
8
Centrifugal pump
9
Aseptic homogenizer
10
Aseptic tank
11
Aseptic filling
12
CIP Legend: Product
Hot Water
Steam
Vacuum and Condensate
Cooling Water
Diverted Flow Product
Figure 11.15 UHT process with heating by direct steam injection combined with plate heat exchanger1
Direct UHT systems feature direct contact between the heating medium and the product. This allows direct steam injection into the product (Figure 11.15). At a temperature of about 4-15ºC, the product enters the sterilizer via a balance inlet tank and a centrifugal feeding pump. It is heated by plate or tubular heat exchangers to about 70-80ºC. At this stage, steam is injected into the product (Figure 11.16), or the product is conveyed into a steam chamber. In infusion systems, the product is infused into a steam chamber so both injection and infusion systems must operate with culinary steam. Steam condensation increases the temperature almost instantaneously to the sterilization temperature, which is typically between 137ºC and 145ºC. At the sterialisation temperature, the average holding time is 4-15 seconds. In both the injection and infusion processes, water condenses in the product and dilutes it.
Figure 11.16 Steam injection nozzle1
1
Figures 11.15-11.16 © Tetra Pak International S.A., Dairy Processing Handbook 2015
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Subsequently, equal amounts of water must be removed. The outlet of the holding cell connects to a vacuum chamber. To prevent boiling in the product-holding cell, a sufficient overpressure by a suitable restriction device must be introduced. When exposed to underpressure, the product starts boiling vigorously and steam is flushed off. Careful adjustment of the injection or infusion temperature and the underpressure in the vacuum chamber guarantees a consistent dry matter content of the incoming and outgoing products. As a result, the pressure drops and requires an aseptic transfer pump to be installed for further product transportation. In order to avoid an accumulation of product in the expansion cooler, both the product feeding pump and the transfer pump at the outlet of the expansion cooler must be carefully matched. The capacity of the transfer extraction pump is often controlled by a sensor immersed in the product, in the vacuum chamber. Then, cavitation forces during steam condensation destabilize protein and fat. To compensate for this effect, direct heating requires downstream homogenization, which has to be done under aseptic conditions. Homogenization pressures for coconut liquid products are usually 150-200 bar. The homogenizer pushes the product through the final cooling section of the sterilizer, either into an aseptic storage tank or directly into the aseptic filling machine. In the expansion cooler, water and other volatile compounds are removed from the product. In addition, the vacuum chamber functions as a very effective deaerator removing oxygen and other dissolved gases, including carbon dioxide (CO2). As a consequence, the freezing point of the product increases.
THE ADVANTAGES OF INJECTION AND INFUSION HEATING • A lower total heat load, which means fewer chemical changes are inflicted on the product • Less scaling, particularly in the temperature range of 70ºC and above, resulting in longer production runs with less frequent cleaning and sterilization required • Low oxygen content in the product increases the stability of some vitamins and reduces flavour changes caused by oxidation during storage • Suitable for products with low and medium viscosity
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Recently, special UHT heat exchangers have been developed to combine direct and indirect heating processes. In one assembly, tubular heating and steam injection were combined. The product enters at around 4-10ºC and is heated to 95ºC by tubular heat exchangers. Steam injection raises the temperature instantaneously to 140ºC. The product is held at this temperature for a few seconds before it is cooled down. Pre-cooling is performed in a tubular heat exchanger where heat is utilized for regenerative heating and the injected steam is flushed off as a vapour in a vacuum cooler. When temperature drops to 80ºC, aseptic homogenization is needed. Subsequently, the product is cooled to ambient temperature and filled aseptically. Product quality from different UHT systems Different UHT systems affect the product quality of coconut milk and coconut water (Tables 11.3 and 11.4). PRODUCT QUALITY OF COCONUT MILK DIRECT UHT
INDIRECT UHT
Fresher product quality
More cooked taste
Recommended for high viscosity/fat content 22-24%
Generally good for 18% fat content. Need more Tubular Heat Exchangers (THE) for heat transfer
Lighter colour
Darker colour
Table 11.3 Effects of different UHT systems on coconut milk
PRODUCT QUALITY OF COCONUT WATER DIRECT UHT
INDIRECT UHT
Fresher product quality
More cooked taste, sometimes coconut aroma is more
Less browning
More browning
Recommended for coconut water
Generally good if it can be adapted to have less THE to lower heat transfer
Table 11.4 Effects of different UHT systems on coconut water
CHAPTER 12
CHILLED COCONUT LIQUID PRODUCTS Pasteurization is a mild heat process that destroys undesirable organisms, including vegetative disease-causing ones. It effectively extends the shelf life of the product. In order to ensure product safety and quality for consumers, there must be an understanding of the many variables involved in pasteurization, including increased hygiene conditions, packaging and chilled distribution.
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CHILLED COCONUT LIQUID PRODUCTS PROCESSING CHILLED COCONUT LIQUID PRODUCTS Pasteurization is a commonly used heat treatment, less severe than UHT, which is suitable for the processing of coconut liquid products.
Pasteurization is a mild heat process that destroys undesirable organisms, including vegetative disease-causing ones. The process is named after the French scientist, Louis Pasteur, who discovered in the 1860s that undesired fermentation could be prevented in wine and beer by heating it to 57°C for a few minutes. Pasteurization eliminates vegetative bacteria in coconut liquid products to ensure food safety, and maintains rigid quality control over both raw and finished products. It can be categorized as low temperature long time (LTLT) pasteurization, high temperature short time (HTST) pasteurization and ultrapasteurization. Each type of treatment requires a specific type of packaging to maximize its effect. Table 12.1 shows the characteristics of different types of heat treatment.
Globally, between a quarter and half of the world’s food supply is lost after harvesting due to spoilage, insect infestation, bacterial and fungal attack. Heat treatment of food
TYPES OF HEAT TREATMENT Pasteurized
SHELF LIFE
PRODUCT TYPE
Days
Chilled coconut liquid products
Ultrapasteurized
Weeks
Chilled coconut liquid products
UHT
Months
Ambient coconut liquid products
Table 12.1 Characteristics of pasteurized, ultrapasteurized and UHT treatments
products is one way of reducing such losses by extending its shelf life.
The typical pasteurization process for coconut liquid products is 75-95° C for 15-120 seconds. In order to ensure product safety and quality for consumers, there must be an understanding of the many variables involved, including increased hygiene conditions, packaging and chilled distribution.
Coconut liquid products are ideal media for bacterial growth and require some form of heat processing for long-term storage. As such, coconut beverages and coconut milk can be quickly processed using pasteurization. This also maintains a rigid quality control over raw and finished products. The process involves mildly heating coconut liquid products, which results in an increased refrigerated shelf life. Pasteurization eliminates vegetative bacteria in coconut liquid products. Overall, the harmful impact of pasteurization on coconut liquid product quality is relatively mild. Although bacterial spores and some heat-resistant, non-disease causing microorganisms can survive the pasteurization process, the total microbial load is substantially reduced. LOW TEMPERATURE, LONG TIME (LTLT) PASTEURIZATION The original heat treatment for dairy milk was a batch process in which dairy milk was heated to 63°C in open vats and held at that temperature for 30 minutes. This method is called the LTLT or holder method. Today, coconut liquid products are more commonly treated in continuous processes like HTST pasteurization and UHT treatment.
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The recommended temperature and time combinations for HTST pasteurization is 75-95°C for 15-20 seconds.
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HIGH TEMPERATURE, SHORT TIME (HTST) PASTEURIZATION In HTST method, the actual time and temperature combination varies according to the quality of the coconut base, the type of product treated, and the required keeping qualities of the product. ULTRAPASTEURIZATION Ultrapasteurization is an extended heat treatment, which aims to extend the coconut liquid products shelf life beyond that of a typical pasteurized coconut beverage. Some manufacturers aim to put two extra days on top of the typical shelf life of a pasteurized coconut beverage, while others aim for an additional 30-40 days. Ultrapasteurization conditions fall between the conditions needed for normal pasteurization and ultra-high temperature treatment. This treatment can vary in different countries, although generally, the product is heated to between 125-135°C for 0.5-4 seconds. Ultrapasteurization is frequently used in the United States and the European Union. In the United States, the common treatment is 138°C for two seconds while for Europe, it is 127°C for two seconds. This process is also known as high temperature pasteurization in some countries. Extended Shelf Life (ESL) is a general term used for ultrapasteurized products which have been given improved keeping qualities. Thus, they are able to retain good quality up to 7°C storage temperature. An ESL coconut beverage has an extended shelf life beyond that of its traditionally pasteurized counterpart. ESL beverages must still be kept refrigerated during distribution. The fundamental principle behind ESL technology is the reduction of reinfection sources during processing and packaging. This requires extremely high levels of production hygiene and low distribution temperature. The lower the temperature, the longer the shelf life. Ideally, coconut beverages like coconut milk should be transported at 4°C, at which the product quality and safety is best maintained (Tan et al., 2015). Ultrapasteurization can be carried out through direct or indirect heat processing. Direct heat processing is most commonly used as it results in a better sensory quality in the finished product. However, during processing, high heat load increases the risk of heat-induced flavour changes in coconut liquid products, which can be reduced by process and line optimisation. All in all, an ultrapasteurized coconut beverage tends to be safer and of better quality compared to a normally pasteurized coconut beverage. This is mainly due to production in a more hygienic and tightly controlled environment.
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Shelf life of ultrapasteurized coconut liquid products For pasteurized coconut liquid products and most pasteurized low acid products, the limiting factor of shelf life is microbiological activity. Ultrapasteurization is able to extend product shelf life, provided the storage conditions are appropriate. Factors affecting the shelf life of ultrapasteurized coconut liquid products include temperature, time, oxygen and moisture. Excessive quantities of these elements cause a loss in nutritional value, producing offflavours, odours, and rancidity.
LDPE* Paperboard LDPE
Type 1 Economical non-oxygen barrier material. Metallized finish is available on the print side for nonbarrier materials.
LDPE Paperboard LDPE Barrier (EVOH**/Nylon) LDPE
Type 2 Non-foil oxygen barrier material for oxygen sensitive products. Metallized finish is available on the print side for plastic barrier materials.
The packaging material used also determines the shelf life of the coconut liquid products. There are three types of laminated carton packaging material (Figure 12.1). Due to barrier properties, the packaging material is able to protect the contents against the transfer of gases, flavour compounds, light and microorganisms into the package. In addition, the packaging material used for ultrapasteurized coconut beverages is disinfected, unlike that of pasteurized coconut beverages.
LDPE Paperboard LDPE Aluminium foil LDPE (modified) LDPE
Type 3 Highest oxygen barrier with aluminium foil, for longest shelf life of oxygen sensitive material.
Figure 12.1 Three different types of laminated carton packaging material * LDPE: Low Density Polyethylene ** EVOH: Ethylene Vinly Alcohol
SHELF LIFE IS THE LENGTH OF TIME DURING WHICH A FOOD PRODUCT CAN BE RELIED UPON TO RETAIN CERTAIN MINIMUM QUALITY CHARACTERISTICS. FACTORS AFFECTING SHELF LIFE OF PASTEURIZED PRODUCTS ARE:
1
Raw product quality
2
Operation and hygiene
3
Processing and storage conditions
4
5
Packaging machine system
Packaging configuration and seal quality
6
Distribution conditions and temperature
7
Consumer handling
In some parts of Central and South America and Asia, both homemade and commercial coconut liquid products are consumed on a daily basis. Commercial coconut liquid products are packed in bulk or individual containers of various types. Through treatments which control the microbiology of the product and appropriate packaging, the shelf life and distribution areas of coconut liquid products can be greatly extended.
Spoilage of the pasteurized coconut liquid products can be affected by the amount of contamination found in the coconuts. Minimal contamination from soil, bacteria and other organisms can be ensured through cleaning. The length of shelf life required determines the pasteurization conditions. The processing equipment also needs to be clean, free from dirt, contaminants, and sanitized to prevent further contamination of the coconut products.
Pasteurization of coconut liquid products, which kills off vegetative bacteria, ensures that the products are safe for human consumption as long as they are refrigerated during their recommended shelf life. The typical shelf life of a pasteurized coconut liquid product is about one week at 4°C.
Minimizing recontamination, along with the cold storage of these products, aids in prolonging shelf life. Pasteurized coconut liquid products are stored, distributed and sold in “cold chain” conditions. Cold chain handling ensures that coconut beverages are stored at a refrigerated temperature from the time of packaging to arrival at retail outlets.
Quality aspects of pasteurized coconut milk and coconut beverages are affected by the quality of raw materials, process parameters, packaging and storage conditions.
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The quality of ultrapasteurized coconut liquid products depends on factors like the quality of the raw material, the processing and storage procedures, packaging, plant hygiene and local distribution conditions. It is important to consider all factors from the raw material stage to delivery on the retail shelf and consumption. The fundamental principle of extended shelf life processing is to minimize microbial load and recontamination (Figure 12.2). This can be achieved by careful consideration of:
1
Raw material selection
2
Processing
conditions
3
Strict hygiene conditions
4
Environmental factors
Figure 12.2 Quality considerations for pasteurized and ultrapasteurized coconut beverages
During processing, ultrapasteurization is employed for ESL beverages as it reduces the microbial load to a much greater degree than pasteurization. Strict hygiene conditions are employed in the processing of ESL beverages. These conditions provide more protection against recontamination from transfer of the product to the filler and the filling environment. In effect, the quality of coconut liquid products fed to the filler is largely maintained through such conditions, and a reduced microbial load is achieved, compared to pasteurized coconut liquid products.
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The extended shelf life concept does not merely include the extension of an end product shelf life. The primary advantages offered by the extended shelf life concept are based on improvements in hygiene over the entire chain of production from the extraction of coconut milk and water, processing and filling, to chilled chain distribution. Through improved product quality and safety, the possibilities of geographic expansion, development of larger markets and production and distribution efficiency are increased. As discussed, the extended shelf life concept involves many factors. The end product quality is the composite result of many variable factors along the entire chain of production, which begins with the quality of the raw coconut material and ends with the quality of the chilled distribution chain. In order to quantify the end product quality and safety, there must be understanding of the many variables that affect product quality. The factors affecting ultrapasteurized coconut liquid products’ quality, safety and shelf life can be broadly categorized as operational, environmental and technological factors (Table 12.2). FACTOR TYPE
FACTORS
Technological1
Preventive Maintenance Operation Equipment Pre-Production Equipment Sterilization Cleaning-in-Place
Environmental2
Hygenic Standard of Operating Environment Raw Material Quality Cold Chain/Distribution Quality of Utilities
Operational3
Package Integrity Performance Line Installation Secondary Packaging Processing & Filling Equipment
Table 12.2 Factors affecting ultrapasteurized coconut liquid products quality, safety and shelf life Relates to help the equipment (including package integrity) Relates to the area where the equipment is situated, operated and the quality of the chill chain 3 Relates to the manner in which the equipment is operated, cleaned and maintained 1 2
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Often only technological factors are considered in shelf life and food safety issues. While equipment continues to be an important factor, there is also a need for increased awareness of the role of the operating environment and the level of skill required by the equipment operator. A balanced approach will ensure a stable foundation for the sustained production of safe and high quality coconut beverages.
DISTRIBUTING AND PACKAGING CHILLED COCONUT LIQUID PRODUCTS The primary objective of chilled distribution is to reduce or eliminate microbial activity and growth when the product is being stored or distributed. This is done through chilling or reduction of the product temperature, followed by refrigerated storage. The process also aims to extend shelf life. Ultrapasteurized or ESL products are clearly distinguishable from UHT products when it comes to distribution and merchandizing. From the consumers’ perspective, ESL coconut beverages will always be judged by the level of pasteurized coconut beverages as they are merchandized from the same refrigerated section in supermarkets. Both traditionally pasteurized and ultrapasteurized coconut liquid products are distributed in all types of packages. They must be stored under refrigeration. Through careful handling, essential nutrients and original flavours are preserved in the products. Different packaging materials and containers are used for different products. These are influenced by processing operations undertaken prior to packaging. The packaging material is selected to maintain the desirable product characteristics as established by the manufacturing process, and to achieve the desired shelf life. Both container type and packaging material can vary. Packaging material used for packing ESL coconut beverages is disinfected with hydrogen peroxide to reduce microbial load. This is unlike the packaging material used for traditionally pasteurized coconut liquid products. Package integrity and stability should be reinforced to ensure product quality during an extended period in a moist and cold environment. General handling and physical damage of the packaging must also be kept to a minimum to ensure package integrity.
NOTES
CHAPTER 13
PACKAGING OF COCONUT LIQUID PRODUCTS Packaging is essential for keeping food products safe for consumption. It primarily aims to contain the liquid product, prevent leakage and protect the contents from physical, chemical and biological hazards, which are present throughout the product’s shelf life.
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PACKAGING OF COCONUT LIQUID PRODUCTS Packaging is essential for keeping food products safe for consumption. It primarily aims to contain the liquid product, prevent leakage and protect the contents from physical, chemical and biological hazards, which are present throughout the product’s shelf life. In the case of coconut liquid products, the choice of packaging is important in ensuring product quality and use. The most suitable packaging material should only be chosen after careful consideration of the desired shelf life and end condition of the coconut liquid product.
ROLE OF PACKAGING Packaging has a major role to play in preserving coconut liquid products, keeping them in a good and wholesome condition. This includes protecting coconut liquid products from microbial spoilage and chemical deterioration, which can be caused by exposure to moisture and air. More importantly, packaging must be able to fulfil the two basic aims of containing the beverage and preventing leakage. It should also protect coconut liquid products from physical hazards throughout its shelf life. The life span of packaging starts from the point of production and packing, to its disposal by the end user. Current consumer trends show a preference for a wide range of coconut liquid products available all year round in various package volumes. With increased urbanisation and busier lifestyles led by today’s consumers, packaged coconut liquid products are fast gaining acceptance. As a means of extending the product shelf life, packaging has become essential in ensuring that the product remains safe for consumption.
METHODS OF STERILIZING PACKAGING MATERIAL There are several methods to sterilize packaging material. Essentially, there are three major sterilization processes used either individually or in combination. These processes are heat treatment, chemical treatment and irradiation.
?
From containers provided by nature to the use of complex materials and processes, packaging has certainly evolved, due to factors like marketplace competition and changing lifestyles. In early times, food containers came in the form of leaves, gourds, shells and even animal organs. When it came to packaging liquids, the first containers were clay jars and wooden barrels. The coconut itself served to contain coconut water. Today, aseptic packaging allows beverages like the coconut water to have an extended shelf life of up to six months or more. It also avoids the need for preservatives or refrigeration by ensuring commercial sterility during processing and packaging.
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HEAT TREATMENT Heat treatment comes in two forms – dry and moist. Dry heat treatment involves the use of hot air in the absence of water molecules. On the other hand, moist heat treatment involves the use of steam, specifically pure gaseous water with no other gases present. In comparison, moist heat treatment is more effective than using dry heat. Nevertheless, both sterilization techniques depend on time and temperature factors. For moist heat treatment to reach temperatures high enough for sterilization to occur within seconds, steam is produced using pressure in a pressure chamber. Here, any air that enters the chamber with the packaging material must be removed to ensure that it will not interfece with heat transfer between the steam and packaging surface.
?
Peracetic acid (PAA) is produced through the oxidation of acetic acid by hydrogen peroxide (H2O2). It is a frequently used liquid sterilant that is effective against spores.
CHEMICAL TREATMENT Chemical treatment is often used to sterilize packaging material. Usually, the chemicals used are hydrogen peroxide (H2O2) and peracetic acid (PAA). Used in combination with heat to sterilize the surface of carton packaging material, H2O2 is effective against microorganisms and resistant spores. For rapid sterilization, high concentrations of H2O2 at high temperatures are required. PAA is a liquid chemical sterilant used for the sterilization of filling machine and plastic packaging material surfaces. IRRADIATION Irradiation can be carried out using pulsed light or ionising radiation. In the case of pulsed light, short high power pulses are emitted by a capacitor that stores electrical energy. These pulses are intense and emit broad spectrum white light that sterilizes aseptic packaging material. A few flashes within a fraction of seconds provide high level microbial inactivation. lonising radiation can sterilize the interior of a sealed empty container with gamma rays. This is suitable for packaging materials which cannot tolerate thermal sterilization, or is restricted by their shape and cannot be conveniently sterilized by other methods. A radiation dose of 25kGy (2.5Mrad) or more is usually applied to ensure sterilization. In the case of the bag in box, an empty, sealed bag is irradiated and placed in a sterile filling chamber. The bag is unsealed, filled and resealed in a sterile environment to prevent any recontamination.
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? Electron beam technology can also improve the environmental performance of the filling equipment by reducing energy consumption.
ELECTRON BEAM TECHNOLOGY Widely adopted to sterilize food packaging, electron beam technology works by focusing a controlled beam of electrons onto the surface of the packaging material. As the packaging material runs through the filling machine, the beam kills any bacteria or micro-organism present, thereby sterilizing the packaging material. Note that the product is not sterilized with the electron beam, only the packaging material is. Compared to chemical treatments, this packaging sterilizing technology allows easier water recycling as there is no need to filter out H202.
SELECTING PACKAGING FOR COCONUT LIQUID PRODUCTS Coconut liquid products are packed to maintain quality under various shelf life conditions. These conditions vary according to raw material quality, processing parameters, storage conditions and the threshold of acceptance by the individual consumer. Note that the packaging can protect the coconut liquid product, but cannot improve its quality over time. When selecting the most appropriate packaging for coconut liquid products, the following factors should be considered. COMPOSITION Coconut liquid products might contain potential delaminators like free fatty acids or other flavours and stabilizers. For example, in some carton laminates, there may be occasional problems caused by free fatty acids or other components of the coconut liquid product. This is true for coconut milk based liquid products which either contain or will develop free fatty acids that react with some packaging material and cause delamination. Free fatty acids and other components found in the coconut liquid product can also attack some laminates and not others, due to the difference in layer properties. Referring to two Tetra Pak laminates in Figure 13.1, the free fatty acids may react with Tetra Brik® Aseptic/m polyethylene and aluminium foil adhesion to create a bag in box. This occurs when free fatty acids attack the bond between the inside layer of the inner polyethylene and the aluminium foil.
?
Carton laminate is a composite of many layers. The combination of traits possessed by each layer adds to the strength of the laminate. As such, delamination weakens the laminate. This increases the risk of product reinfection and degenerating quality. The packaging also becomes difficult to open for consumption. Choosing the right laminate according to the product is important to ensure this does not happen.
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If the package used for the coconut liquid product is Tetra Brik Aseptic/m, the attack is often rapid and may result in the complete delamination of the inner polyethylene from the aluminium foil. As a result, the inner polyethylene may be detached from the package and look like a ‘bag in box’. This significantly increases the oxygen migration surface. On the other hand, bag in box does not occur in the other type of laminate (Tetra Brik Aseptic/j). In the Tetra Brik Aseptic/j material, the inside polyethylene layer next to the aluminium foil is made from a modified polyethylene containing a high level of acrylic acid. The acrylic acid results in stronger binding with the aluminium foil. However, if free fatty acids are present, they will inevitably migrate through the polyethylene and, in time, the acrylic acid bond will be replaced by the free fatty acid molecules. The level of acrylic acid in the adhesive layer of Tetra Brik Aseptic/j is set to provide reasonable resistance against delamination by free fatty acids in ambient conditions over normal shelf life.
Figure 13.1 Cross section of two types of carton laminates
In another example, coconut liquid products may also have a suspension of very fine powder, especially if it is recombined from coconut powders. Such powder particles may affect the transversal seal. Therefore, it is important to understand the biochemistry of the product and its ingredients, in order to suitably determine the choice of laminate. QUALITY PARAMETERS Quality parameters, such as flavour, colour and microbiological quality changes may be caused by several factors. Some of these are subjected to the flavour transfer within the package, as well as the entry of oxygen, light or microorganisms into the package. As such, the packaging requires barriers to deter these factors from entering the coconut liquid product. In the case of carton laminates, the aluminium foil layer within the laminate can provide most of the barrier required.
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EXPECTED SHELF LIFE Depending on the length of the shelf life, the packaging material is required to protect the coconut liquid product for an extended time period. Note that the expected shelf life is highly dependent upon the quality of raw material used, processing parameters employed and the consumer’s threshold of product acceptance. STORAGE CONDITIONS Storage conditions, specifically time and temperature, can affect the quality of the coconut liquid products. As storage conditions are subjected to changes, no one packaging system can completely prevent quality changes from taking place in the product.
A packaging with the right protection for the product, coupled with the right price, design and messaging, can appeal to your target market. This will increase the likelihood of consumers reaching out for your unique branded product
CONSUMER COMMUNICATIONS Besides protecting the coconut liquid product, packaging also acts as a communication medium to consumers. It is useful in conveying information to consumers. These information include the date of manufacture, expiry dates, nutritional information, ingredients and certifications (e.g. Kosher, Halal, Organic) according to each country’s food law regulations and requirements. Packaging also helps draw consumers closer to the product and brand by communicating your brand personality through the logo, graphics and stories.
through various distribution channels.
PORTION SIZES Packaging comes in different sizes. Where consumption is in small volumes, portion packages (less than 600ml) are generally suited for children and adults to finish coconut beverages in one seating. These portion sizes are also suitable for packaging coconut milk or cream, as these products are typically used in small amounts in different food recipes. Where consumption is in large volumes, family packages and large size containers are typically bottled in 1000ml to suit in-home consumption of coconut beverages, as well as for hotel, restaurant, café or catering (HORECA) usage of coconut milk.
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ASEPTIC PACKAGING In aseptic packaging, commercially sterile liquid products are filled into sterile containers under sterile conditions. These containers are then sealed to prevent re-infection. Compared to non-aseptic packaging, aseptic packaging allows the use of containers which are typically unsuitable for in-package sterilization. Through a thermally efficient high temperature, short time (HTST) sterilization process, aseptic packaging results in superior quality products, as compared to those processed at lower temperatures for longer times. This extends the product shelf life at ambient temperatures. For coconut liquid products, aseptic packaging can help distribute and store these perishable goods without refrigeration for more than six months. The aseptic packaging system achieves room temperature shelf stability by filling a sterilized package with sterilized coconut liquid products, all within the confines of a hygienic environment. This is different from other systems that use preservatives and refrigeration to prolong the product’s shelf life. For storing coconut liquid products at ambient temperatures, it is important that these products are commercially sterile when packed, and not re-infected by a contaminated packaging material. Therefore, it is important that the packaging material is properly sterilized, providing an effective barrier against external microorganisms.
? For many decades, aseptic packaging has been widely used in Europe and Asia. It was only introduced to the United States in the early 1980s.
PACKAGING SYSTEMS FOR COCONUT LIQUID PRODUCTS Different packaging systems are used for packaging coconut beverages, milk and cream. For pasteurized and extended shelf life coconut liquid products, non-aseptic packaging material and systems are preferred. In the case of long life coconut liquid products, aseptic packaging is essential. The choice of packaging material used is influenced by the product characteristics, the cost of both the product and the packaging, as well as consumer preferences. The most commonly used consumer package for aseptic products is the laminated carton. The aseptic packaging system fills the sterile product in an aseptic manner, and hermetically seals the package to ensure that sterility is maintained during handling and distribution processes. Commercial requirements of less than one faulty package out of 10,000 packages produced are common. There are five major categories of aseptic packaging equipment available.
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CARTON BASED PACKAGES In most countries, laminated carton packages are the predominant form of packaging for coconut liquid products. Most of these are aseptically packed. Non-aseptically packed coconut liquid products using chilled distribution can also be found. The material used in carton based aseptic packages is normally made up of a barrier layer, and layers of paperboard coated internally and externally with polyethylene rendering. It is impermeable to liquids. Today, the most commonly used material for the barrier layer is the aluminium foil, which acts as a barrier to oxygen, flavour and light. Other barriers include SiOx on polyester, ethylene vinyl alcohol (EVOH) and polyamide (PA).
Figure 13.3 Carton-based packages
The structure of a typical paperboard carton is shown in Figure 13.2. The polyethylene coat on the outer layer protects the carton against environmental moisture, while the paper layer provides stiffness and strength. Another layer of polyethylene bonds this base paper to the barrier layer, which protects itself against the entry of light, gas and other materials. The last inner layer of polyethylene acts as a sealing (Figure 13.3). For proper functioning, the packaging material should be stored at the temperature and humidity levels recommended by the manufacturer. 1
Polyethylene - protects against outside moisture
2
Paper - for stability and strength
3
Polyethylene - adhesion layer
4
Aluminium foil - oxygen, flavour and light barrier
5
Polyethylene - adhesion layer
6
Polyethylene - seals in the liquid
Figure 13.2 Structure of packaging material
?
THE INTERACTION BETWEEN THE PACKAGING MATERIAL AND THE STORED PRODUCT IS INEVITABLE. INTERACTIONS CAN COME IN THE FORM OF: • MIGRATION Compounds from the packaging material, such as polyethylene coating, print and base paper, can dissolve into the product. The presence of aluminium foil limits migration. • ADSORPTION Product ingredients adhere to the inner surface of the packaging material • ABSORPTION Product ingredients are absorbed into the inner surface of the packaging material. • PERMEATION Product ingredients pass to the outside of the package, or compounds from the outside penetrate into the container. Gas permeation can take place through the seams of a container through the longitudinal seam. A multi-layered barrier strip provides better barrier characteristics than a strip with one or more layers of polyethylene.
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CARTON-BASED PACKAGES FROM PREFABRICATED BLANKS A pre-fabricated system produces pre-fabricated cartons such as the gable top. First, blanks are die cut and creased, while the longitudinal seal is completed at the packaging material plant by skiving the inner layer of board and folding it back. These blanks are delivered to the beverage packaging facility in lay flat form for shaping and bottom sealing. In the extended shelf life (ESL) application, the hygiene area of the filling machine consists of several separate functional zones where operations are carried out in sequence. Hygiene is maintained in each zone by a slight overpressure of sterile air. The inside surface of the carton is disinfected with hydrogen peroxide (H202) solution delivered either as a fine spray or as peroxide vapour in hot air, so that the vapour condenses as liquid peroxide on the carton surface. The peroxide is then removed by a jet of hot air. After filling, the top seal of the carton is folded and closed. A prefabricated blank is shown in Figure 13.4.
Figure 13.4 A pre-fabricated carton blank
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CARTON-BASED PACKAGES FROM ROLLS Carton-based packages produced from rolls are pre-printed and pre-creased. They are respectively known as Tetra Brik® and Tetra Prisma® packages from Tetra Pak. First, the packaging material is sterilized using a wetting system or a deep bath system. The wetting system involves the application of a thin hydrogen peroxide film containing a wetting agent. In the deep bath system, the packaging material is fed through a deep bath containing hydrogen peroxide. Next, the sterilized material is fed into a machine where the material is shaped into a tube and the longitudinal seal is secured by heat sealing. A strip that had been added prior to sterilization is heat sealed across the inner surface of the longitudinal seal to prevent contact between the outside and inside of the carton. It also provides protection of the aluminium and paperboard layers from the product, which could corrode or swell the layers if such a strip were absent. After the longitudinal seal is formed, the coconut liquid product is then filled into the tube and a transversal seal is made below the level of the product to ensure that the package is completely filled. The sterilization, filling and sealing processes are performed inside a chamber that has undergone sterilization prior to production and is maintained at an overpressure of 0.5 atm with sterile air. Some carton-based packages made from rolls are shown in Figure 13.5.
Figure 13.5 Roll-fed packages
Another type of carton-based package from Tetra Pak is Tetra Top®, which is a carton package with a polyethylene lid. It is usually made from roll-fed packaging material. The packaging material is folded in the machine, sealed longitudinally and cut into sleeves. The plastic tops are injection-moulded and applied to the packages. After filling, the bottoms are sealed by heating elements. Besides laminated carton packaging, coconut liquid products can also be packaged using plastic pouches and bottles, glass bottles and metal cans.
?
In the case of aseptic filling, the coconut liquid product is UHT treated using a high temperature short time (HTST) process. This limits energy use and nutrient loss through flash heating and cooling. As a result, the final coconut liquid product may also possess a more natural colour, taste and texture.
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BOTTLES Plastic bottles Different types of plastics can be used to bottle coconut liquid products. Over recent years, blow moulded plastic bottles made from high density polyethylene (HDPE) or polypropylene have been commonly used. Sometimes, pigments are added into these materials to act as a light barrier. Multi-layer plastics with improved barrier properties have also been developed. High-density polyethylene (HDPE) High-density polyethylene (HDPE) is a member of the polyolefin group produced through an extrusion blow moulding (EBM) process. As a highly crystalline material, it boasts high impact strength, chemical resistance and thermal stability. As HDPE is relatively oxygen-permeable, plain HDPE bottles are well suited for coconut liquid products with limited shelf lives. As the material is permeable to gases, other polymers can be introduced to improve its ability to block oxygen. Such bottles have up to seven layers for maximum light and gas barrier properties. The most common barrier layers are ethylene vinyl alcohol (EVOH) and polyamide (PA), which allow ambient storage of beverages for more than six months. HDPE bottles are also fairly opaque and often pigmented. In general, HDPE provides reasonable barrier properties, a stiff and strong structure, good resistance to chemicals and moisture, and is easily processed and shaped. Polyethylene-terephthalate (PET) Polyethylene-terephthalate (PET) bottles are made by stretch blow moulding using a preform. They are colourless and transparent, although pigments can be introduced. A preform is an injection moulded PET tube closed at one end while a finished neck is formed at the open end. When blown, the stretching gives tensile strength and gas barrier properties to a lightweight bottle that is relatively low in cost. For coconut liquid products which contain a high concentration of polyunsaturated fatty acids that can be rapidly oxidized, plastics that are minimally permeable to gases are highly preferred.
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A PET bottle is more robust than glass but is more gas-permeable. Barrier properties for PET bottles improve with increased crystallinity, which is in turn, influenced by material thickness and conditions during stretch blow moulding. Barrier improvement is also possible through the introduction of new compounds, a barrier coating or making several material layers using a preform. For aseptic filling, PET bottles are first sterilized before the coconut liquid product is added. During sterilization, bottles are treated with hydrogen peroxide or a mixture of hydrogen peroxide and peracetic acid, then rinsed with sterile water. They are usually of lower weight than hot fill bottles and do not require heat setting. As a result, they are cheaper and more flexible in design. Glass bottles Glass bottles can be used to contain coconut liquid products with hot or aseptic filling techniques. It is produced using the blow and blow, or press and blow method. Over the years, glass has developed into a sophisticated form of packaging. Scuff resistance has been increased through light weighting and surface coating, while plastic coating materials are also used to coat glass. This plastic coating acts as a surface protector and pre-label base, helping to absorb impact, reduce noise and provide insulation. Glass bottles also come in new “wide-mouth” versions with easy-to open caps. These are generally produced by the press and blow method. To make good glass bottles, attention must be given to the quality and strength of the glass material during production. These include raw materials silica sand, soda ash, limestone, dolomite and cullet. After mixing, the raw materials are charged into a melting furnace and refined before being forced through an orifice, emerging as a gob of molten glass. Then, it goes into a forming machine, to be turned into the shape of a bottle by compressed air.
?
In 1940, when polyethylene-terephthalate (PET) was discovered by Whinfield and Dickson in England, ethylenglycol and terephthalate combinations were jointly poly-condensed to form a polymer. This was dried into thin rods, cooled and grounded into granules which were crystallized and heated to form a colourless PET-granulate. This is when the molecule chains become so flexible that the plastic melts, turning into a slightly fluid material that can be shaped into practically any form. As the material cools, the molecular chains freeze in position and the plastic hardens into the desired shape.
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FLEXIBLE POUCHES Flexible pouches are categorized as wholly plastic or plastics, fibre and aluminium combinations. Plastic pouches are usually made up of five layers, one tie layer connects the printed polypropylene to a proprietary centre barrier, which acts as a gas and water barrier. Another tie layer comes before an inner polyethylene sealant layer.
Figure 13.6 Tetra Fino® is made up of six layers. It has no rigid geometrical shape and may have openings like straw holes.
Using either two or three piece metal cans, coconut liquid products can be heat sterilized with their beverage contents.
A plastic pouch is light and stands by itself. It also allows direct printing onto the package. Sometimes, spouts made out of high density polyethylene are also attached. However, as the spout can compromise the space inside the pouch, straw holes can be used instead. Alternatively, a flexible pouch of plastic, fibre and aluminium combination with no rigid geometrical shape can be used (Figure 13.6). CANS Typically, three-piece cans are two parts made of steel while the third part is fitted with an aluminium easy-open end. Both parts in the three-piece can are soldered, welded or side-seam bonded by adhesive. For two-piece cans, there is an integral body and bottom fitted with an aluminium easy-open end. A three-piece can is made by printing and base-lacquering sheets of tinplate, which are then cut into rectangular shapes of the appropriate size. These rectangles are first shaped and soldered. Next, lacquer side-stripes are applied over the internal solder margins. The cylinders formed are then flanged at both ends. Depending on the diameter, manufacturers can help to fit the steel or easy-open end. Finally, the open-topped cylinder is sprayed with a second coat of lacquer. To reduce the cost of producing the aluminium end, ‘necking-in’ the can’s body can be adopted to reduce the diameter of the end. The production process of a two-piece can consists of a few stages. First, the cup-maker machine converts the coiled feedstock into circular discs. Then, they are held in a controlled die gap and drawn or pressed into the required cup shape. Next, cups received from the cup-maker are redrawn to the basic can diameter and progressively forced through car-bided ring discs and stretched to the desired can length. In this process, can wall thickness is reduced by up to 70%. Last but not least, a doming punch at the end of the stroke produces a bottom configuration to suit design requirements. Cans are then necked in and flanged in a special machine, covered with two coats of lacquer sprayed onto the internal surface of the can.
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PACKAGING DESIGN INNOVATION Innovative packaging designs can help products stand out on the shelves. Typically, coconut liquid products can be packaged in five different carton formats. In addition, there are six other formats of cartons from Tetra Pak to choose from. TETRA BRIK® ASEPTIC A familiar portfolio to consumers worldwide, Tetra Brik® Aseptic is the world’s best-selling carton package range for liquid food. Easy to distribute, stack and store, it is available in volumes ranging from 80-2000ml.
TETRA BRIK® ASEPTIC 200 BASE
TETRA BRIK® ASEPTIC 200 SLIM
TETRA CLASSIC® ASEPTIC Available in fun, unique shapes, Tetra Classic® Aseptic also appeals to consumers with its easy to squeeze and drink mechanism. From the kitchen counter to the school desk, this packaging stably contains liquids everywhere.
TETRA CLASSIC® ASEPTIC 65
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TETRA PRISMA® ASEPTIC Tetra Prisma® Aseptic offers a distinctive prismatic shape that instantly stands out on the shelves. Its eight-sided shape, with metallized and non-metallized print options, provides unlimited creative branding opportunities. In addition, it is designed to naturally fit in your hands, ensuring a good grip with easy opening and pouring functions made easy with smart openings and convenient caps.
TETRA PRISMA® ASEPTIC 330
TETRA PRISMA® ASEPTIC 500
TETRA PRISMA® ASEPTIC FAMILY (1 LITRE)
TETRA FINO® ASEPTIC Tetra Fino® Aseptic is made easy for everyone. Retailers will find this format easy to pack, stack store, promote and replenish. Likewise, consumers can easily carry and store these products at home. Last but not least, they are child-friendly, made easy for children to hold.
TETRA FINO® ASEPTIC 70
TETRA FINO® ASEPTIC 150
TETRA REX® Commonly found in the refrigerated sections of retail channels in the United States, Europe and Oceania, Tetra Rex® is a chilled package designed to protect fresh products where chilled distribution is established. Offering a broad portfolio of packages and closures, this format is also customisable based on the choice of board, barrier and print. TETRA REX® HALF GALLON
Typically, coconut liquid products can be found in the above mentioned packaging formats. Shelves can also be refreshed with newer formats like Tetra Brik® Aseptic 200ml Slim Leaf, Tetra Brik Aseptic 200 Crystal, or made more appealing with convenient formats that have added caps like Tetra Brik Aseptic 250E Helicap23, Tetra Gemina® Aseptic and Tetra Top®.
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SOME OTHER PACKAGES FROM TETRA PAK THAT COCONUT LIQUID PRODUCTS CAN BE FOUND IN
TETRA GEMINA® ASEPTIC 1500
TETRA BRIK® ASEPTIC 200 EDGE
TETRA BRIK® ASEPTIC 250 EDGE
For more packaging varieties and options, please visit www.tetrapak.com
CHAPTER 14
QUALITY PARAMETERS AND QUALITY CONTROL METHODOLOGIES For any food product, quality is subjected to consumer perceptions of taste, mouthfeel and colour. This is also true for coconut liquid products.
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QUALITY PARAMETERS AND QUALITY CONTROL METHODOLOGIES For any food product, quality is subjected to consumer perceptions of taste, mouthfeel and colour. This is also true for coconut liquid products. As coconut water, milk and cream are increasingly consumed worldwide, the quality of coconut liquid products can be better determined by objective assessments. Several quality parameters, which differ in chemical composition, can define the makeup of each product. These parameters refer to the chemical, microbiological, nutritional and physical factors that make up the coconut liquid products its unique properties, which also influences the products shelf life. For example, as coconut water and milk are low-acid and high water activity foods, they become highly susceptible to microbial spoilage and deterioration.
Note The suggested range of values are not applicable to all coconut types and varieties. They could be subjected to variations in coconut maturity,
That said, research studies are still not extensive enough to cover all aspects of coconut liquid products. Therefore, this chapter serves as a guide by attempting to consolidate and recommend possible quality control methods to objectively define coconut liquid products and suggest a range of values for each parameter. It is important that experienced quality control personnel and statisticians are employed to conduct quality checks and shelf life studies for these products.
variety, cultivation practices and more. In addition, postharvest factors, such as packaging, transportation and storage conditions can also influence the composition of coconut liquid products.
The recommended quality control parameters are shown in Table 14.1. All tests should be done before and after aseptic processing and packaging. However, for boxes which are not ticked, it is optional or of less importance to do so for the respective products. Analytical methods for the respective quality parameters are also recommended in CODEX STAN 247-2005, unless otherwise stated. COCONUT WATER BASED PRODUCTS
COCONUT MILK BASED PRODUCTS
Flavour/odour
√
√
Total soluble solids °Brix
√
√
Dry matter determination
√
√
pH/ titratable acidity
√
√
Microbiological content
√
√
Sulphite test
√
√
Browning index determination
√
Optical density/ Turbidity test
√
TEST
Free fatty acids determination
√
Viscosity
√
Table 14.1 Important quality control tests for liquid coconut products
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Besides flavour, all listed parameters can be determined by standard methods of analysis to give meaningful and reliable results. This is because flavour and odour is commonly evaluated by sensory means, usually by groups of panellists. These analysis methods were collected and published in books such as Guidelines for Sensory Analysis in Food Product Development and Quality Control (Carpenter et al., 2008) and Sensory Evaluation by Quantitative Descriptive Analysis (Stone et al., 1974).
QUALITY CONTROL METHODOLOGIES AND SUGGESTED QUALITY PARAMETERS TOTAL SOLUBLE SOLIDS Total soluble solids is an important quality parameter in many food products. Its analysis is also a commonly practiced one. It typically indicates the amount of dissolved sugars in the product, thus affecting both safety and hedonic properties. It can be measured using a refractometer, which calculates the total soluble solids of the sample in °Brix, and is more important for coconut water. COCONUT LIQUID PRODUCT
Infrared drying is a fast method of dry matter or total solids analysis. It is a faster method compared to oven drying.
SUGGESTED °BRIX RANGE
Young coconut water (7-9 months)
5.5-8.0
Mature coconut water (10-13 months)
3.5-6.0
DRY MATTER OR TOTAL SOLIDS ANALYSIS The analysis for dry matter or total solids can be done by oven or infrared drying. In oven drying, direct heating is used to dry the sample, followed by manual weighing. These analyses are more so important for coconut milk and cream, which standards have been defined by CODEX STAN 240-2003. TEST METHOD
PROCEDURE
Oven drying
The sample is weighed before and after drying, and drying takes place in an oven. Knowing the difference in original and dried weight corresponds with the moisture mass, and the percentage of dry matter can be calculated.
Infrared drying
An infrared or halogen moisture analyser is an automated machine which gives the moisture or dry content reading of the sample without a need for further manual calculation.
Table 14.2 Dry matter analysis methods
COCONUT LIQUID PRODUCT
SUGGESTED PERCENTAGE RANGE OF TOTAL SOLIDS
Light coconut milk
6.6-12.6
Coconut milk
12.7-25.3
Coconut cream
25.4-37.3
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pH MEASUREMENT pH is a crucial parameter for food as it indicates the sourness of a product and its current shelf life stability. For coconut water and milk, the pH measurement drops over the course of its shelf life, until it is exceeded. Using a calibrated pH meter, the pH of a sample may be measured. COCONUT LIQUID PRODUCT
SUGGESTED pH RANGE
Young coconut water (7-9 months)
4.5-5.3
Mature coconut water (10-13 months)
5.3-5.8
Coconut milk and cream
At least 5.9
TITRATABLE ACIDITY (TA) In coconut water, TA is expressed as the percentage of malic acid equivalent. More specifically, TA is determined as the malic acid equivalent by titration of a sample against 0.1N NaOH. The sample is titrated until pH 8.2. The sample can be diluted where required.
Titratable acidity (TA)= (N x M x V1 x 100)/V2
WHERE N = normality of NaOH used M = malic acid factor (67.05) V1 = titre volume V2 = volume of coconut water added
COCONUT LIQUID PRODUCT
SUGGESTED % OF TITRATABLE ACIDITY
Young coconut water (7-9 months)
0.07-0.09
Mature coconut water (10-13 months)
0.05-0.08
MICROBIOLOGICAL TESTING Microbiological testing can be measured as the Total Aerobic Count (APC), as well as Yeast and Mould Plate Count (YMPC). First, samples are collected and used to prepare serial dilutions of the samples. Then, diluted samples buffered at pH 7.2 are placed onto agar plates or petri films with different kinds of nutrient media available to culture microorganisms for APC and YMPC. Thereafter, the diluted samples are incubated at 37°C for 24-48 hours for APC. For YMPC, they are incubated at 25°C for 3-5 days, or as stipulated by regulations (US FDA, 2001). Taking into account the dilution factor, the colony forming units are calculated in the original sample and checked against the local authority’s compliance standards for quality control.
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SULPHITE TEST Sulphite test can be used to determine the amount of sulphite residue in coconut water, milk and beverages. There are many ways to do so. In this chapter, we will cover two methods, using sulphite test strips and DTNB test. For a faster and approximated result, sulphite test strips may be used. For a more accurate result, the DTNB test may be used. TEST METHOD
PROCEDURE
Sulphite Test Strip
First dip the test strip into the sample. Compare the colour of the strip with the standard printed on test package after a stipulated amount of time (e.g. 30 seconds). Depending on the test strip supplier, the instructions might vary slightly.
DTNB Test
For the standard curve construction, first prepare the DTNB1 solution, diluted in phosphate buffered saline solution (pH 7.2). Then prepare the standard solutions of 0.1 to 5 ppm sodium metabisulfite. For 1 mL of each of these standard solutions, add 1mL of DTNB and top up to 10 mL with distilled water. From these standard solutions, record the absorbance at 412 nm after 5 minutes of reaction at room temperature. Finally, construct a standard curve of absorbance against SMB concentrations.
The original SMB concentration= (y/m) x DF WHERE y = the absorbance reading (at 412nm) of the sample m = the slope obtained from the standard curve DF= the dilution factor (10/0.5)
For sulphite content measurement, mix 0.5 mL of sample solution with 1mL of DTNB and top it up to 10 mL with distilled water first. Record the absorbance at 412 nm after 5 minutes. Using the standard curve, find the concentration of the diluted sample. Note that the volume of coconut sample used for the reaction may be adjusted as necessary for the absorbance result to fall within the range of the standard curve.
Table 14.3 Sulphite test methods 1
Ellman’s reagent - 5,5’-Dithiobis-(2-Nitrobenzoic Acid)
The residual levels of sulphite in the coconut liquid products are regulated by laws and changes between countries. It is recommended to consult with the regulatory experts in the respective countries.
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Colour Browning in coconut water Browning is an especially prevalent problem in coconut water. It is a visual component of the product that is often used as an indicator of shelf life acceptability, even though browning by itself may not be indicative of product spoilage. The browning index reflects the cumulative browning of all pathways, including enzymatic and nonenzymatic occurrences in coconut water. Examples are Maillard reaction and ascorbic acid browning. The standard for acceptable browning is set by the individual company or customers. The browning index (BI) is calculated as the difference between the absorbance at 420 nm and 550 nm (to correct for turbidity). The absorbance of the samples are first recorded at 420nm (A420) and 550nm (A550), then the Browning index is calculated.
Browning Index (BI)= A420 - A550
WHERE
A420 = absorbance at 420 nm A550 = absorbance at 550 nm (to correct for turbidity)
Using samples with different degrees of browning, construct a browning scale index and establish a standard. For example, Index 9 of BI 0.055 (Figure 14.1).
1
0.000 (Water)
2
0.020
3
0.025
4
0.030
5
0.035
6
0.040
7
0.045
8
0.050
9
0.055
10
0.060
11
0.070
12
0.080
Figure 14.1 Browning index scale for coconut water
1
2
3
4
5
6
7
8
9
10
11
12
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Pinking in coconut water Pinking is caused by an intermediate in the polyphenol oxidasecatalysed browning reaction and is typically found in young coconut water only. It is an indication of cracks in young coconut, which lead to the exposure of coconut water to the external environment. COCONUT LIQUID PRODUCT
Studies show that for coconut milk, the “L” values can range from 70.5-88.0 while “b” values can range from 4.2-8.6. The values are affected by
SUGGESTED COLOUR STANDARD
Young coconut water (7-9 months)
Should not be pink, if browning occurs less than index 9 of BI 0.055
Mature coconut water (10-13 months)
Less than index 9 of BI 0.055
Discolouration in coconut milk Coconut milk normally appears as creamy white. Due to reactions such as browning, it may be discoloured, forming a brown, greyish or off-white colour. The colour of coconut milk is also affected by oil globules. In general, when there are small and numerous droplets, the reflectance off the oil globules give a white colour.
homogenization and different temperatures. For example, homogenization has shown an increase in lightness at 30°C when “L” values in coconut milk increased from 77.92 up to 80.59. (Chiewchan, 2005; Waisundara et al., 2006)
The colour of coconut milk can be analysed by measuring the reflectance with a colorimeter to obtain three Hunter parameters, namely “L” lightness, “a” red or green component and “b” yellow or blue component. L and b can be used to describe the change in colour of coconut milk (Chiewchan, 2005). A two-axis scale can also be set up for the colour of coconut milk using “L” and “b” values. Although tedious, this scale is valuable to have. Optical density or turbidity test Optical density can be used as a measure to indicate the colour of the product sample. A cut-off point above or below a sample is deemed to have passed its shelf life. It should be determined by the specific product requirements. Using an appropriately calibrated spectrophotometer, absorbance of samples are recorded at 600 nm. Using a series of samples from various times in its shelf life, set a standard for quality control of the sample. Turbidity is an important quality parameter for coconut water, as customer’s acceptability may decrease as turbidity increases. Turbidity can be measured using a turbidimeter to establish a standard. This is a faster method to measure the clarity levels of coconut liquid products. This test is more important for coconut water as coconut milk is naturally opaque. COCONUT LIQUID PRODUCT
SUGGESTED TURBIDITY (NTU)
Young coconut water (7 - 9 months)
Less than 50
Mature coconut water (10 - 13 months)
Less than 100
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More commonly, free fatty acid (FFA) values are specified for desiccated coconut and coconut cream powder products. They are a maximum of 0.2
Free fatty acids (FFA) measurement FFA is commonly a product of fat hydrolysis. It is therefore an indicator of spoilage in foods. The presence of FFA is usually associated with the onset of rancidity and off-flavour development, which is especially important in foods with significant fat content, such as coconut milk and cream.
and 0.3% respectively. Some specificationsfor coconut cream show FFA content to be a maximum of 0.15%.
Titration method is used to measure FFA content in a food sample. First, titration of the product is carried out against a standard NaOH solution, with phenolphtalein as an indicator. For coconut products, FFA is usually a reflection of its free lauric acid content which has a major presence. WHERE
FFA (% lauric acid equivalent)= (V×N×M)/(10×G)
V = ml of NaOH used N = normality of NaOH used= 0.1 G = weight of sample in g M = average molecular weight of the fatty acids (mostly lauric acid for coconut products)
* Please note that the sample may be diluted as necessary
Note Viscosity affects the pourability of the product from the package. There are no suggested ranges for the viscosity of coconut cream. Analysis of commercial samples at Tetra Pak in-house rheology lab (RheoLab) shows that, at a shear rate of 100s-1 with temperature of 30°C between 17-25.1% of oil content, the viscosity of coconut milk can range from as low as 8 mPas to as high as 260 mPas.
Viscosity measurement Viscosity measurement is used to determine the thickness of the product, thus relating to the filling component in the production run, as well as the product’s mouthfeel and stability. Using a temperature controlled Brookfield viscometer, the viscosity of a product can be measured at different shear rates. These measurements characterize the rheological behaviour of the tested sample and are important in the designing and fine tuning of aseptic line solutions in terms of packaging and processing equipment. This measurement is more applicable for coconut milk and cream, where the product can be very thick, depending on the formulation and process parameters (e.g. homogenization pressure). It is generally observed that coconut milk and cream increases its viscosity with storage time. Please refer to Chapter 10 for more details.
GUIDELINES TO TAKING VISCOSITY MEASUREMENTS 1. The temperature is kept constant during the test period for accurate measurement. - A temperature change of 3ºC can cause at least 10% change in viscosity. - As some products are more temperature sensitive than others, it is even more crucial to keep the temperature constant. 2. To further increase the accuracy of data evaluation, measurements should be made at as many different shear rates and temperatures as possible. 3. When utilizing different temperatures, heating effects must also be considered. For example, the viscosities of warm swelling starch differs significantly before and after heating. 4. Other factors include storage and time. For example, if the purpose is to supply data for process design, the measurements should be made as near to the actual processing stage as possible. 5. Proper instrumentation and experimental procedure should also be established.
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ACCELERATED SHELF LIFE Coconut liquid products are packaged to maintain quality during its defined shelf life conditions. Shelf life depends on several factors, such as raw material quality, processing parameters, storage conditions and the threshold of acceptance of the individual consumer. It cannot be determined in terms of time by the packaging material supplier. Although processing and packaging can protect the contents, it cannot improve the quality of the coconut liquid products if they were produced from bad raw materials. ACCELERATED SHELF LIFE DETERMINATION (ASLD) ASLD is used to shorten the time required to estimate a shelf life, which otherwise can take an unrealistically long time to determine. As the food trade globalizes and competition in the food market intensifies at national and international levels, there is a greater need to quickly determine shelf life within a shorter time period. This situation becomes more pressing when shelf life is expected to range from several months to a few years. Therefore, the set up for ASLD usually involves increasing the product’s storage temperature to accelerate time required to reach the end of its shelf life. The typical storage temperature for ASLD studies are as follows: FOOD CATEGORY
CONTROL TEMPERATURE (°C)
ASLD TEMPERATURE RANGE (°C)
Refrigerated
2
5-15
Shelf-stable
22
30-45
Table 14.4 Typical storage temperature for ASLD study
As most reaction rates increase exponentially with a rise in temperature, increasing the temperature by 10°C can cause quality loss to increase by a factor of 2-6. This simplified factor, known as Q10, depends on the food being evaluated, the mode of failure, and the temperature range. To calculate the Q10 factor, the product is stored at three to four different temperatures within the specified range. Each temperature is constantly maintained within 1°C, and the ASLD temperature range is usually raised slightly above the control temperature. This helps to avoid changes in the product failure mode.
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Besides elevated temperatures, additional ASLD conditions are also occasionally employed. These include elevated humidity, oxygen tension in the headspace and cycling temperature fluctuations. However, the complexity of these factors require special mathematical data manipulation, which makes their application quite cumbersome. Accelerated shelf life testing requires careful methodology. As such, a number of test conditions must first be made before the study. TEST CONDITIONS OF ACCELERATED SHELF LIFE TESTING 1. The appropriate quality factor or index of deterioration a. For example, the maximum microbial count limit set by the authority, or maximum browning index as the maximum acceptable limit 2. Storage temperature 3. Additional ASLD conditions a. For example, humidity 4. Control and the number of replicates 5. Total storage time 6. Number of variables a. For example, coconut water with or without antioxidants 7. Kinetic models *Source: Graf et al.,1991
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RECOMMENDED EXPERIMENTAL SET-UP FOR COCONUT LIQUID PRODUCTS After a specified treatment and storage duration, the recommended experimental set-up for the estimation of shelf life is as follows: STORAGE TEMPERATURE (°C)
EQUIPMENT
4
Refrigerated incubator
25 30 40
High temperature incubator
55 Table 14.5 Recommended temperatures for shelf life study
TEMPERATURE (°C)
WEEK NO.
INTERVALS (NO. OF WEEKS)
4
25
30
40
55
0
-
√
√
√
√
√
1
1
√
√
√
√
2
1
√
√
√
√
4
2
√
√
√
√
6
2
√
√
√
8
2
√
√
√
12
4
√
√
√
16
4
√
√
√
20
4
√
√
24
4
√
√
28
4
√
√
Table 14.6 Recommended intervals for the shelf life study of coconut liquid products
In general, it is expected that products stored at higher temperatures will have a shorter shelf life. Thus, shelf life study for samples stored at higher temperatures may end sooner. In comparison, samples stored at 4°C can be expected to last at least three months without any significant change in quality. Tables 14.5 and 14.6 may be adjusted to fit the conditions where necessary.
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The browning index of coconut water as a limiting factor to determine the shelf life of long life coconut water is illustrated below. First, packed coconut water samples at four different temperatures are stored for up to seven months (28 weeks). At each storage interval, samples are removed and analysed for the browning index. When stored, there will be a gradual increase in the browning index of the coconut water throughout the storage period. A RELATIONSHIP BETWEEN SHELF LIFE AND BROWNING INDEX CAN BE DETERMINED WITH THE FOLLOWING STEPS: 1. Record absorbance of the samples at 420nm (A420) and 550nm (A550), and calculate the Browning index. Browning index (BI) = A420 - A550 2. Determine the rate of reaction at each storage temperature by plotting a graph of browning index (ln A/A0) against storage duration. a. Where A is the browning index of the sample and A0 is initial browning index 3. From this graph, the reaction rate is obtained as: a. Slope = -k, where k is the reaction rate for each storage temperature 4. Repeat steps 2 and 3 for a minimum of three storage temperatures. Based on the k values obtained from the different storage temperatures, plot shelf life against storage temperature on the graph.
Shelf life is calculated based on the following equation: WHERE
tS = ln (A0–Ac)/k
tS A0 AC k
= the shelf life = initial browning index = the maximum acceptable browning index (e.g. AC=0.55) = the reaction rate
CHAPTER 15 CLEANING OF PROCESSING EQUIPMENTS
Cleaning of processing equipments is an important step in the manufacturing process, especially when they come in contact with food products. Overall, food manufacturers are obliged in many ways to maintain high hygienic standards for both their equipment and staff.
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CLEANING OF PROCESSING EQUIPMENTS Cleaning of processing equipments is an important step in the manufacturing process, especially when they come in contact with food products. Overall, food manufacturers are obliged in many ways to maintain high hygienic standards for both their equipment and staff. Cleaning helps the food manufacturing company ensure that good products are kept well and safe for consumption. This minimizes the risk of contamination, which can result in very bad publicity. Companies are also morally obliged to ensure that clean conditions and well-trained staff are put in place to ensure that production processes are properly handled. Lastly, the law protects the health and quality of manufactured food products. Failure to meet legal guidelines can result in severe penalties, which is why it is important to meet the stated requirements accordingly.
COCONUT FOOD SOIL FORMATION In order to design an efficient Cleaning-In-Place (CIP), knowledge of how mechanical, thermal and chemical processes work on different types of soiling is required. It will also depend on knowing how acids and detergents affect different types of soiling and how their interaction can be optimized. In the parallel passages of plate or tubular heat exchangers, different amounts of deposits are formed on different surfaces. This mainly consists of protein, fat (oil) and minerals at higher temperatures. Overall, coconut soil deposit formation is affected by the nature of the product; quality of the raw materials used to form primary and intermediate products; actual product temperature; temperature difference; flow rate of the product (laminar or turbulent); characteristics of the heat exchange surface (corroded or dirty) and foam in the product. Water-insoluble soils can be divided into organic soils and inorganic soils.
Soils can initially be divided into two basic types: those that are water-soluble and insoluble in water. Water-soluble soils such as sugars and some minerals are easily removed and are rarely associated with cleaning problems. The water-insoluble soils are harder to remove.
CHAPTER 15 | CLEANING OF PROCESSING EQUIPMENTS
Alkaline detergents remove organic soil, such as protein and fats.
Acid detergents remove inorganic soil, such as mineral deposits.
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Organic soils include fats, oils, grease, protein, starch and other carbohydrates. If these components were heated during processing, the heat may have induced reactions in the soil matrix. This makes them harder to remove. For example, proteins may, denature and induce further cross-linking reactions with other protein molecules. They may also react with carbohydrates and cause Maillard reactions (caramelization) to take place. Organic soil is most often dissolved by alkaline detergents. Inorganic soils include mineral and salt deposits. The most common inorganic soil is limescale, formed due to high water hardness. Inorganic soils are most often dissolved by acid. FOULING Fouling, in relation to concentrations of proteins, fats (oil) and minerals, can be classified as physical precipitation or chemical fouling. Total amount of fouling and distribution between both types are temperature-dependent. In general, the amount of fouling increases with temperature. The proportion of chemical fouling caused by denaturation of protein also increases with temperature. At low temperatures between 50-54.5°C, flow rate becomes a determining factor for fouling. As flow rate decreases, there is a thicker laminar layer indicated by a decrease in the Reynolds number. This in turn promotes sedimentation, and physical fouling increases. Physical precipitation can be due to fats (oil) accumulation. In coconut liquid products, particularly coconut milk, the protein acts as an emulsifier for fat (oil) molecules in aqueous media. However, coconut milk’s naturally low amount of protein content in proportion to its oil content might not be enough to emulsify all the oil globules. As a result, the emulsion is destabilized, and flocculation and coalescence occur. In other words, fat (oil) globules aggregate. At high temperatures between 60-74.5°C or at 90°C, chemical fouling is formed. It consists of denatured protein deposits. This is due to protein denaturation as coconut protein denatures at about 80°C. With less fat percentage in this deposit, there is also less effect on flow rates.
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CLEANING IN PLACE (CIP) Cleaning cooking vessels at home is performed by hand. In the food industry this is called “cleaning out of place”, or COP. All equipment is dismantled and cleaned manually. For manual cleaning, industrial brushes and gloves must be available (see Figure 15.1). Only mild chemicals with pH values between 4 and 9 are used. It is difficult to achieve consistent results because staff is involved. Motivation, training, close supervision and education are required to ensure consistency and efficiency. Figure 15.1 Cleaning industrial brush © Tetra Pak International S.A., Dairy Processing Handbook 2015
Today COP, cleaning out of place, has been replaced with CIP, cleaning in place, in most parts of the food industry where food is pumped and undergoes continuous processes. Some equipment still needs to be dismantled and manually cleaned, but wherever possible, CIP is the preferred choice.
CIP is important in guaranteeing food safety in food processing plants. Successful cleaning between production runs avoids potential contamination and products that do not meet quality standards. Carrying out CIP correctly, from design to validation, ensures secure barriers between food flows and cleaning chemical flows. It is also important that CIP is carried out effectively and efficiently, and contributes to an overall low total cost of ownership (TCO). From the point of view of food processing, any cleaning time is downtime – the equipment is not productive. Cleaning must also be carried out safely, because very strong chemicals are involved that can be harmful to people and the equipment. Finally, it should be carried out with the least impact on the environment, by using minimal amounts of water and detergents, and by maximizing the re-use of resources. There are two ways of performing CIP. Either the cleaning detergents are put to drain immediately after they have been used. This is called single-use cleaning and is often used when the object is very dirty, such as a UHT plant. The other alternative is when less dirty objects are cleaned, such as tanks or pipes that have cold surfaces. The cleaning solution is not that dirty after one cleaning cycle and it can be reused. This is usually referred to as recovery CIP. Both methods have advantages and disadvantages. In single-use the cleaning solution is always fresh when cleaning is started and the equipment needed to perform single-use CIP is rather inexpensive. On the other hand, this way of running CIP has a high running cost and a high environmental load, as the cleaning solutions are always drained and disposed. By recovering the cleaning solutions, less cleaning detergent will be consumed, as well as less water and energy. The equipment needed to recover the cleaning solutions is, however, more expensive than the equipment needed for single-use cleaning.
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CLEANING PARAMETERS Soil is held on the surfaces by adhesive forces. To get the soil to leave a surface the forces that hold the impurity on the surface have to be overcome. There are four parameters that make up cleaning and should be controlled during cleaning: mechanical force, thermal force (heat), chemical force and the time the forces act (Figure 15.2).
Figure 15.2 Forces acting on soil during cleaning
Energy is required in a cleaning process in order to remove the soil, once dissolved keep it in solution and carry it away. The energy required is kinetic, chemical and thermal energy. These three factors, together with the contact time are the most important regarding effectiveness of the cleaning. These four parameters are interconnected and depend on each other. It is usually called the Sinner´s circle and include flow, temperature, concentration and time (Figure 15.3)
CO NC EN
FLOW ION AT R T
TE MP E
RE TU RA TIME Figure 15.3 Sinner’s circle of four parameters of cleaning
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Flow Flow creates the shear forces that in turn, creates the mechanical force in cleaning in place. Compare cleaning a car with and without a nozzle on the water hose. With a nozzle the area through which the water is passing is restricted. This increases the velocity of the water and the water jet gets “harder”. In a plant, the flow of the cleaning liquids can be increased by pumping it faster. The CIP flow has several purposes – transport the CIP liquid to the soiled surface, react with the soil and finally remove the dissolved soil and transfer it out of the equipment being cleaned. As a general rule it is said that the flow must be turbulent and that the flow velocity should be a minimum of 1.5 m/s to have an adequate mechanical force during CIP.
Heat exchangers are designed to create a turbulent flow but connecting pipes must also have proper characteristics. Due to flow restrictions, a bypass and a special “cleaning pump” may be necessary to help create the turbulent flow. For cleaning aseptic tanks, the inner tank surface must be completely covered. A spray device (Figure 15.4) is also required every two metres in horizontal tanks, and they must be controlled properly and serviced regularly.
Figure 15.4 Spray turbine for tank cleaning © Tetra Pak International S.A., Dairy Processing Handbook 2015
CHAPTER 15 | CLEANING OF PROCESSING EQUIPMENTS
In formulated detergents different cleaning aiding components are also added, which for instance can take care of hard water, suspend the dissolved dirt better than pure
171
Type and concentration of detergents Detergents are used to get soil to leave a surface based on chemical force. To clean equipment, chemicals have to be used in combination with the mechanical force, the flow. Most often alkaline detergents are used first. They dissolve most organic soil like protein, fat and sugars. The detergent can be pure sodium hydroxide or it can be a formulated detergent based on NaOH from a detergent company.
NaOH, wet the surfaces more efficiently and more.
After an alkaline cleaning step, an acid step usually takes place. Acid dissolve minerals like inorganic soil. It has some effect on fat, sugar and protein as well. Acids commonly used are nitric acid or phosphoric acid. Types of detergents Detergents can range from pure chemicals such as sodium hydroxide (lye), nitric acid or phosphoric acid to more complex formulated detergents supplied by detergent companies. A third alternative is adding additives to a pure chemical, such as sodium hydroxide, at the food manufacturer. This is a very flexible alternative where you might use only pure chemical for some cleaning objects and create a formulated detergent for others. It is important to follow the dosage recommendations for the detergents and correctly calculate and dilute the concentrates with water. DETERGENT ALTERNATIVES:
1
Pure chemicals - Sodium hydroxide, nitric acid, phosphoric acid
2
Formulated detergents - Pure chemicals + additive
FORMULATED DETERGENTS HAVE CERTAIN AGENTS ADDED TO INCREASE CLEANING EFFECTIVENESS. THE MAIN COMPONENT OF ALL FORMULATED DETERGENTS IS ALWAYS AN ALKALI OR AN ACID. ADDITIONAL COMPONENTS CAN INCLUDE: • Surfactants, or wetting agents that lower surface tension, enabling them to wet a surface more effectively and make cleaning more efficient. • Sequestering agents can bind calcium and magnesium ions to soften water. • Complex-forming agents can only bind one metal ion per molecule in contrast to sequestering agents, which can bind a number of metal ions. • Oxidation Agents can boost cleaning effects. Examples are sodium hypochlorite and hydrogen peroxide.
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THERE ARE IN PRINCIPLE TWO WAYS OF PREPARING DETERGENT SOLUTIONS IN PROCESSING EQUIPMENT:
1 2
Single-use case (most often for heating units such as sterilizers and pasteurizers) The detergent concentrate is dosed directly into a water-filled processing unit. Recovery case The detergent solutions are prepared in the correct dilutions in a special cleaning station. The detergent solutions are prepared in detergent tanks in which the detergent is recovered after cleaning. When preparing detergent solutions, start with a fixed volume of water into which a certain volume of concentrate should be dosed. These liquids are then pumped through the processing equipment while cleaning.
Concentration of detergent The chemical concentration depends on the kind of soil to be removed. Heated surfaces often require higher concentrations than cold ones. Detergent concentrates have to be diluted with water before they can be used. The final concentration is important, since too low or too high a concentration may result in inadequate cleaning. Concentrations that are too high also waste money and damage the equipment. After preparation of the detergent solutions, it is important to also measure that the correct concentration has been achieved. For example, a conductivity measuring device with a guarding and recording function can be installed for a continuous inline measurement of the concentrations. As a general rule a plant should be cleaned at the same temperature as it has been processing the food. If a higher cleaning temperature
Temperature Temperature is controlled in cleaning . Thermal force, heat is used to move molecules faster at an elevated temperature and therefore increase the effectiveness of a detergent at an increased temperature.
is used than the processing temperature, reactions such as denaturation and cross linking may be induced by the higher temperature during cleaning making the soil harder to remove.
Time The fourth and last parameter is time. Most surfaces will be cleaned but it will take a longer time if the optimal temperature is not used. Incorrect concentration of detergent and insufficient flow also leads to a longer time spend cleaning.
CHAPTER 15 | CLEANING OF PROCESSING EQUIPMENTS
CLEANING PROCEDURE CIP for coconut liquid product processing plants generally follow a default programme and cleaning agents. The engineers in the processing plants can fine tune the programme based on customer’s products.
THE PROCEDURE FOR CLEANING A PLANT OFTEN FOLLOWS THE ORDER BELOW: 1. FLUSHING The plant is flushed with water to remove any loose soil (if high fat product, use lukewarm water). 2. PRE-RINSE The plant is pre-rinsed with water at 40-60°C, to remove sugar and melt any fats. The temperature should not exceed 60°C in order to avoid denaturing any native proteins, which then become much more difficult to clean. 3. ALKALINE STAGE Alkaline detergent is circulated in the system to remove organic soil such as proteins and fats. Alkali is added to the concentration set-point and the temperature is raised to the temperature set-point. The flow is kept at a level that gives satisfactory flow velocity. The alkali step lasts for a pre-set time period. 4. FIRST PURGING Water is used to purge out the alkaline detergent and the dissolved soil. 5. ACID STAGE Acidic detergent is circulated through the plant, to dissolve mineral deposits caused by hard water, scaling. The frequency of when an acidic step is applied depends on whether the surfaces are hot or cold, the type of food and the water quality. During the acid step concentration, flow and temperature is kept at its setpoint for a pre-set time period. 6. SECOND PURGING AND FINAL RINSE Water is used to purge the acidic detergent and rinse out dissolved soil. The final water rinse must also ensure that any detergent residues are removed and only water is left in the plant. The plant should now be visibly clean. 7. DISINFECTION OR STERILIZATION Disinfection or sterilization is applied before production starts to kill bacteria or other living organisms to a certain level.
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WATER QUALITY WATER HARDNESS Water hardness is of great importance. This measures the amount of calcium and magnesium in the water (Table 15.1). When hard water is heated, calcium carbonate is precipitated. Carbon dioxide and water is formed as well. If equipment is sterilized with hard water, calcium carbonate will precipitate throughout the plant. Scaling of CaCO3 is, however, easily removed with acid cleaning. Calcium salts may also interfere with detergents and make them less efficient. Water with a hardness above 7°dH needs to be softened to a hardness between 4-7°dH (Table 15.2). WATER HARDNESS
Water hardness can be
RANGE (°dH)
expressed in German degrees
Soft
0-6
(°dH) or mg CaCO3/L (or ppm).
Medium hard
6-12
Hard
12-18
Very hard
> 18
1°dH = 17.9 mg CaCO3/L
Table 15.1 Classification of water hardness
CHLORINE CONTENT OF WATER If chloride (Cl-) and chlorine (Cl2) levels in water are too high, this will cause corrosion of stainless steel. In summary • Total hardness: between 4-7°dH • Chlorine content: less than 0.2 ppm • Chloride content: less than 30 ppm • pH value higher than 7
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THE CIP SYSTEM An entire CIP system consists of a station, distribution lines and the objects to be cleaned. There are in principle two types of CIP system – centralized or decentralized. Centralized CIP systems are most efficient in small plants where there are short distances between the CIP station and the cleaning objects. Centralized systems are also common in relatively large plants where all CIP activities are handled from a centralized cleaning room with one or several CIP stations. Cleaning liquids and water are then pumped from the central CIP stations to the various cleaning objects. Decentralized CIP systems are more common in large plants where the distances from a centrally located CIP station to the cleaning objects can be extremely long. Instead of using one central CIP room, the decentralized CIP system utilizes several distributed stations (Figure 15.5), positioned close to the cleaning objects. In a decentralized CIP system, it is still common to handle the detergent concentrates centrally. They are then individually distributed to the CIP stations.
1
Heat exchanger
2
Pressure pump
3
Dosing pumps
Figure 15.5 CIP station
In a food plant, there are many cleaning objects that should be grouped into larger clusters based on what types of cleaning they demand. For example, cold and hot surfaces – since several cleaning stations are often needed. Cleaning of equipment handling nonheat-treated food like raw products should be separated from the cleaning of equipment handling heat-treated food. This is to avoid contaminating surfaces on the processed side with potential surviving bacteria and spores from the raw side, by using the same cleaning liquids on both sides.
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EFFLUENTS ORGANIC EFFLUENTS The presence and quantities of organic substances in sewage effluents are analysed using chromatography. The usual way to express the concentration of a pollutant is to specify the total quantity per unit volume of sewage. The quantity of organic substances is determined in the form of biological oxygen demand (BOD). It measures the content of biologically degradable substances in sewage. Microorganisms use oxygen to break down these substances, so oxygen demand is measured by the quantity of the gas consumed by these organisms, over a period of five days (BOD5) or seven days (BOD7), in decomposing organic pollutants in waste water, at a temperature of 20ºC. Both COD/BOD ratios indicate how biologically degradable an
BOD is measured in mg oxygen/l or g oxygen/m3. This relationship is assumed for municipal sewage: BOD7 = 1.15 X BOD5.
effluent is. For example, values less than 2 indicate that the effluent comprises of relatively easily degradable substances. A typical value of COD/BOD for municipal sewage effluent is less than 2.
The quantity of organic substances can also be determined by chemical oxygen demand (COD). This measures the quantity of pollutants in water, which can be affected by chemical oxidants. The normal reagents used for measurement are highly acidic solutions (to ensure complete oxidation) of potassium dichromate or potassium permanganate at high temperature. The rate of consumption of the oxidant provides a measure of the organic substance content. It is converted to a corresponding measure of oxygen such as mg oxygen/l or g oxygen/m³. INORGANIC EFFLUENTS Inorganic components of sewage from coconut plants consist of salts, and are determined by ionic compounds and salt concentration present in water from the mains. These salts are normally unimportant, as modern effluent treatment is concerned with the reduction of nitrogen, phosphorus salts and heavy metals. Nitrogen and phosphorus salts are nutrients for organisms such as algae, which can cause secondary processes and form further organic substances. When these substances decompose, they can cause higher oxygen demand than that of primary organic pollutants.
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Waste water can be divided into cooling, sanitary waste and industrial waste water. Cooling water is normally free from pollutants as it is usually not mixed with industrial waste water. While sanitary waste water is normally piped direct into the sewage treatment plant, whether it has been mixed with industrial wastewater or not. Lastly, industrial waste water is gathered from product spillage and cleaning processes. The concentration and composition of waste products depend on production, operating methods and plant design. While sewage treatment plants can handle organic substances, fat represents a particularly difficult problem. Besides having a high BOD, it sticks to the walls of the mains and causes sedimentation problems in the sedimentation tank by rising to the surface of the water. To properly treat this wastewater, it should pass through a flotation plant where it is aerated with dispersion water – water with finely-dispersed air bubbles at a pressure of 400-600kPa. The air bubbles stick to the fat and carry it to the surface where it can be skimmed off, either manually or mechanically. The defatted effluent can then be mixed with sanitary wastewater piped to the treatment plant. Preventing water wastage and controlling its use is essential in every processing plant. Hidden losses of water in underground or subfloor piping should be detected by reading the water meter and recording the quantity used at the end of the day. Daily records of water consumption should then be compared with the daily quantity of products processed. Water consumption, expressed as m3 per tonne of treated product, should be plotted on a graph, kept in an easily accessible place. The “wastes” from the production of coconut liquid products can be used for different purposes. Here are some examples of how they can be used for other value-added products (Table15.2). “WASTE” FROM THE PRODUCTION OF COCONUT LIQUID PRODUCTS
USAGES
Dried press residue
Coconut flour, low-fat desiccated coconut, animal feed
Husk, pairings and shell
All can be burnt for fuel and energy. In particular, husk can make rope and mattresses. Shell is used to make activated carbon
Residual oil
Used for fuel and energy
Table 15.2 Different uses of by-products
REFERENCES Principal Literature
Supporting Literature
Chan E, Elevitch CR. Cocos nucifera (coconut). Special Profiles for Pacific Island Agroforestry. 2006.
Ahmad N, Nubaidillah O. Physical characteristics of young nuts from different coconut varieties for use as fresh drink. Proceedings National Coconut Conference 2009: Opportunities for a Sunrise Industry: Damai Laut, Perak (Malaysia). 2010.
Foale M, Harrier H. Farm and forestry production and marketing profile for coconut (Cocos nucifera). http://agroforestry.net/scps. 2011. Hagenmaier RD. Coconut aqueous processing. 1980.
Asian and Pacific Coconut Community (APCC). APCC Standards for virgin coconut oil. 2009.
Tan TC, Ali GRR, Easa AM, Cheng LH, Bhat R. The science of young (tender) coconut water, second phase report. 2012.
Appaiah, P, Sunil L, Kumar PKP, Krishna AGG. Composition of coconut testa, coconut kernel, and its oil. Journal of the American Oil Chemists’ Society. 2014.
Tan TC, Cheng LH, Bhat R, Rusul G, Easa AM. Composition, physicochemical properties and thermal inactivation kinetics of polyphenol oxidase and peroxidase from coconut (Cocos nucifera) water obtained from immature, mature and overly-mature coconut. Food Chemistry. 2014.
Au WF. A study on the development of edible components of the coconut fruit. Proceedings National Coconut Conference 2009: Opportunities for a Sunrise Industry: Damai Laut, Perak (Malaysia). 2010.
Tan TC, Easa AM. The evolution of the physicochemical and microbiological properties of extracted green and mature coconut water (Cocos nucifera) under different storage conditions-report 3B. 2015.
Banzon JA, Velasco JR. Coconut production and utilization. Philippine Coconut Research and Development Foundation, inc (PCRDF). 1982. Baptist NG. Free amino-acids in the endosperm of the endosperm of the developing coconut x (Cocos nucifera). Oxford Journals. 1962.
Tan TC, Easa AM. Studies on the “fate” of sodium metabisulfite in coconut water & Physicochemical and microbiological changes in untreated coconut water. 2014.
Batugal P, Rao VR, Oliver J. Coconut Genetic Resources. International Plant Genetic Resources Institute. 2005
The Coconut Committee. The Philippines recommends for coconut. Philippines Recommends Series. 1992.
Bhagya D, Prema L, Rajamohan T. Beneficial effects of tender coconut water on blood pressure and lipid levels in experimental hypertension. Journal of Cell and Tissue Research. 2010.
Woodroof JG. Coconuts: Production, Processing, Products. 1979. Dairy Processing Handbook, 2015, © Tetra Pak International S.A. Soya Handbook, 2006, © Tetra Pak International S.A. Cleaning-in-place Handbook, 2015, © Tetra Pak International S.A.
Brandt M. Amino acid breakdown. 2003. Carmel A. P., Charles F. D., Lia W. L. , Lastus K., Titus K. Putative Vectors of a Phytoplasma Associated with Coconut (Cocos nucifera) in Madang Province, Papua New Guinea International Journal of Agriculture and Forestry. 2014. Carpenter RP, Lyon DH, Hasdell TA. Guidelines for sensory analysis in food product development and quality control. 2012. Castro FD, Sumague J, de Villa D. How to produce nata de coco. Technology and Livelihood Resource Centre. 1994.
Supporting Literature Chandrasekhara MR, Ramanatham G, Rama Rao G, Bhatia DS, Swaminathan M, Sreenivasan A, Subrahmanyan V. Infant food based on coconut protein, groundnut protein isolate and skim milk powder. Journal of the Science of Food and Agriculture. 1964.
Methods in Molecular Biology. 2011. Food and Agriculture Organisation of the United Nations. Good Practice for the Small-scale Production of Bottled Coconut Water. 2007. Fennema OR. Food Chemistry. 1985.
Chiewchan N, Phungamngoen C, Siriwattanayothin S. Effect of homogenizing pressure and sterilizing condition on quality of canned high fat coconut milk. Journal of Food Engineering. 2005.
Fife B. Water of Life. Coconut Water for Health and Healing. 2008. Fife B. The coconut oil miracle. 2004.
Coconut Development Board of India, Plant protection http://www.coconutboard.nic.in/protect1.htm#erio Codex. Codex standard for desiccated coconut. CODEX STAN 177-1991. Codex. Codex standard for aqueous coconut products: Coconut milk and coconut cream. CODEX STAN 240-2003. Codex. Codex general standard for fruit juices and nectars. CODEX STAN 247-2005. Codex. Recommended methods of analysis and sampling. CODEX STAN 234-1999. Connecticut Coconut Company. Product technical specifications: Coconut milk. Damar S. Processing of coconut water with high pressure carbon dioxide technology. 2006. DebMandal M, Mandal S. Coconut (Cocos nucifera L.: Arecaceae): In health promotion and disease prevention. Asian Pacific Journal of Tropical Medicine. 2011. Department of Agriculture and Cooperation, India. Production and marketing of coconut in India. 2008. Dia VP, Garcia VV, maybesa RC, Tecon-Mendoza EM. Comparative Physicochemical Characteristics of Virgin Coconut Oil Produced by Different Methods. The Philippine Agricultural Scientist. 2005. Engelmann F, Malaurie B, N’nan O. Plant Embryo Culture: Methods and Protocols. Chapter 6 In vitro culture of coconut (Cocos nucifera L.) zygotic embryos.
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REFERENCES Supporting Literature H.T.R. Wijesekara, L. Perera, I.R. Wickramananda, I. Herath, M.K. Meegahakumbura, W.B.S. Fernando and P.H.P.R. de Silva Preliminary Investigation on Weligama Coconut Leaf Wilt Disease: A New Disease in Southern Sri Lanka, Coconut Research Institute. 2011. Jackson J, Gordon A, Wizzard G, McCook K, Rolle R. Changes in chemical composition of coconut (Cocos nucifera) water during maturation of the fruit. Journal of the Science of Food and Agriculture. 2004.
Maciel MI, Oliveira SL, da Silva IP. Effects of different storage conditions on preservation of coconut (Cocos nucifera) water. Journal of Food Processing and Preservation. 1992. Magat, S.S. Production Management of Coconut (Cocos nucifera, Linn.). Diliman, Quezon city, Metro Manila: PCA-ARDB. 67p. 1999. Man D. Shelf life. Food Industry Briefing Series. 2002.
Jangchud K, Puchakawimol P, Jangchud A. Quality changes of burnt aromatic coconut during 28-day storage in different packages. LWT Food Science and Technology. 2007.
Manisha DM, Shyamapada M. Coconut (Cocos nucifera L. Arecaceae): In health promotion and disease prevention. Asian Pacific Journal of Tropical Medicine. 2011.
Kacem B, Cornell JA, Marshall MR, Shireman RB, Matthews RF. Nonenzymatic browning in aseptically packaged orange drinks: Effect of ascorbic acid, amino acids, and oxygen. Journal of Food Science. 1987.
Marina AM, Che Man YB, Amin I. Virgin coconut oil: Emerging functional food oil. Trends in Food Science and Technology. 2009.
Kalman DS, Feldman S, Krieger DR, Bloomer RJ. Comparison of coconut water and a carbohydrateelectrolyte sport drink on measures of hydration and physical performance in exercise-trained men. Journal of International Society of Sports Nutrition. 2012. Kellard B, Busfield DM, Kinderlerer JL. Volatile offflavour compounds in desiccated coconut. Journal of the Science of Food and Agriculture. 1985. Krotkiewski M. Value of VLCD supplementation with medium chain triglycerides. International Journal of Obesity. 2001. Long K, Koh SP, Azali A, Abdullah R. Research and development of virgin coconut oil in Malaysia. Proceedings National Coconut Conference 2009: Opportunities for a Sunrise Industry: Damai Laut, Perak (Malaysia). 2010.
Lopez-Villalobos A, Dodds PF, Homung P. Changes in fatty acid composition during development of tissues of coconut (Cocos nucifera L.) embryos in the intact nut and in vitro. Journal of Experimental Botany. 2001.
Marina AM, Che Man YB, Nazimah AH, Amin I. Antioxidant capacity and phenolic acids of virgin coconut oil. International journal of Food Sciences and Nutrition. 2009. Marten B, Pfeuffer M, Schrezenmeir J. Review: Mediumchain triglycerides. International Dairy Journal. 2006. Mathew AG, Parpia HAB. Food Browning as a Polyphenol Reaction., In: Chichester, Mrak and Stewart, Advances in Food Research. 1971. Ministry of Fisheries, Crops, and Livestock. Postharvest handling technical bulletin. Technical Bulletin No. 27. 2004. Mohpraman K, Siriphanich J. Safe use of sodium metabisulfite in young coconuts. Postharvest Biology and technology. 2012. Monro JA, Harding WR, Russell, CE. Dietary fibre of coconuts from a Pacific atoll: Soluble and insoluble components in relation to maturity. Journal of the Science of Food and Agriculture. 1985. Naik A, Venu GV, Prakash M, Raghavarao KSMS. Dehydration of coconut skim milk and evaluation of functional properties. CyTA – Journal of Food. 2013
Supporting Literature Nair KPP. The Coconut Palm. The Agronomy and Economy of Important Tree Crops of the Developing World. 2006. Nizat MN, Top OM, Hanim ABM, Senik G. A feasibility study on setting up a factory producing carbonated drink from matured Cocos nucifera nuts. Universiti Putra Malaysia. 2010. Nwangwa EK, Aloamaka CP. Regenerative Effects of coconut water and coconut milk on the pancreatic β– Cells and cyto architecture in alloxan induced diabetic Wistar albino rats. American Journal of Tropical Medicine and Public Health. 2011. Ohler JG. Modern coconut management: Palm cultivation and products. Food and Agriculture Organization of the United Nations. 1999. Petchpirun C. Young nut development of Nam Hom varieties (Thai Aromatic coconut). Presented in the seminar entitled “Economical development of Thai aromatic coconut (Nam Hom varieties) for domestic consumption and exportation”. 1991 Philippines Coconut Community. Production of coconut flour and virgin coconut oil. Philippines Coconut Authority, Coconut Industry Production Status, Growing Zones, Productivity and Potential to Increase Nut Supply in Coconut Farms through Practical and Efficient Farming Technologies (PEFT). 2010 Pirmansah A, Asian & Pacific Coconut Community (APCC). World production of coconuts in whole nuts, 2009-2013. Coconut Statistical Yearbook 2013. 2014. Pirmansah A, Asia Pacific Coconut Community (APCC). World production of coconuts in copra equivalent, 20092013. Coconut Statistical Yearbook 2013. 2014. Prades A, Dornier m, Diop N, Pain JP. Coconut water uses, composition and properties: a review. Fruits. 2012. Priya SR, Ramaswamy L. Tender coconut water—nature’s elixir to mankind. International Journal of Recent Scientific Research. 2014.
Punchihewa PG, Arancon RN. Coconut: Post-harvest operations. Asian and Pacific Coconut Community. 1999. Purkayastha MD, Kalita D, Mahnot NK, Mahanta CL, Mandal M, Chaudhuri MK. Effect of L-ascorbic acid addition on the quality attributes of micro-filtered coconut water stored at 4°C. Innovative Food Science and Emerging Technologies. 2012. R. Ramjegathesh, G. Karthikeyan, L. Rajendran, I. Johnson, T. Raguchander & R. Samiyappan, Root (wilt) disease of coconut palms in South Asia – an overview. Archives of Phytopathology and Plant Protection. 2012. Raghavendra SN, Raghavarao KSMS. Effect of different treatments for the destabilization of coconut milk emulsion. Journal of Food Engineering. 2009. Ratanachinakorn B. Postharvest handling of young tender nut. Paper presented at APCC-DOA International Training on the Processing of Value-Added Coconut Products. 2013. Rethinam P. Coconut water—Nature’s Health Drink. Asian & Pacific Coconut Community. 2006. Santos, G.A., P.A. Batugal, A.Othman, L. Baudouin and J.P. Labouisse. Manual on standardized research techniques in coconut breeding. IPGRI, Rome. 100 pp. 1995. Salil G, Nevin KG, Rajamohan T. Arginine rich coconut kernel protein modulates diabetes in alloxan treated rats. Chemico-Biological Interactions. 2011. Seow CC, Gwee CN. Review: Coconut milk: Chemistry and technology. International Journal of Food Science and Technology. 1997. Simuang J, Chiewchan N, Tansakul A. Effects of fat content and temperature on the apparent viscosity of coconut milk. Journal of Food Engineering. 2004. Siriwongwilaichat P, Thongart K, Thaisakornphan P. The effect of blanching on texture and colour of frozen young coconut meat. Food and Applied Bioscience Journal. 2014.
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INDEX A
Page
Acidity........................................................... 29, 78, 81 Titratable acidity .......................................... 156 Aerobic reactions ....................................................80 Agroecology ............................................................44 Agronomic characteristics ......................................40 Altitudes for coconut growth .................................45 Amino acids.....................................27, 33-34, 84, 94 Antioxidants ascorbic acid ...................................................83 sodium metabisulphite ........................... 83, 93 B
Page
Brix ................................................................. 81, 155 Browning.....................78-80, 88, 128, 158-159, 164 C
Page
Calcium in coconut water .............................................26 in coconut kernel ............................................36 as an additive ..................................................98 for water quality ..................................... 97, 174 Caramelization .........................................................80 Chemistry of changes with high heat treatment ........ 117 of coconut milk and cream ...................... 85-94 of coconut water ....................................... 75-84 Chilled products beverages..................................... 102, 130-135 coconuts (whole or trimmed)........................54 Chlorine/chloride in coconut kernel ............................................36 in fertilizer .................................................. 45-46 water quality content............................. 97, 174 Cleaning cleaning in place (CIP) .........................168-170 detergents .................................... 167, 171-172 effluents .................................................176-177 procedure..................................................... 173 Colour .................................................................... 158 of coconut milk or cream ............. 88, 128, 159 of coconut milk powder.................................68 of coconut water ................... 78, 128, 158-159 of crude coconut oil .......................................66 of flour..............................................................68 of nata de coco ...............................................71 of RBD coconut oil..........................................67 of virgin coconut oil................................. 65, 67 water quality parameter.................................97 also see browning and pinking
C (cont’d)
Page
Composition of coconut ................................................. 24-25 of coconut kernel ..................................... 30-36 of coconut milk and cream ........................... 87 of coconut water........................... 26-29, 76-77 of coconut water concentrate....................... 60 of copra ........................................................... 31 Consumer........................................................... 11-12 consumer communication .......................... 142 Copra ..................................................................31, 56 Creaming....................................................89-91, 111 Cytokinins................................................................. 20 D
Page
Dehusking of coconut............................................. 55 Deshelling of coconut............................................. 55 Desiccated coconut ......................................... 69-70 Discolouration .......................................... 78, 88, 159 also see browning and pinking Diseases........................................................ 47, 49-50 Distribution .................................................................. ambient ................................................ 102, 143 chilled ................................................... 102, 135 Drilling of coconut....................................... 58, 81-82 Dry matter ............................................................. 155 Drying of copra..................................................56, 66 E
Page
Electrolytes.........................................................19, 29 Emulsifiers ................................................. 91, 93, 111 Endosperm.................................................. 24, 26, 30 Enzymes.................................................28, 76, 79, 88 Enzyme activity ........................................................ 79 ESL beverages ....................................................... 131 Extraction.................................................................. 59 Also see dehusking, deshelling, paring and drilling of coconut F
Page
Fatty acids ..........................................................32, 65 Free fatty acids ...................................... 94, 141 Free fatty acids measurement .................... 160 Fertilizers ............................................................ 45-46 Flavour .................................................................... 155 of coconut milk and cream ........................... 88 of coconut kernel ........................................... 36 of coconut water....................................... 77-78 of virgin coconut oil ....................................... 67 of coconut milk powder ................................ 68 Food soil......................................................... 166-167 Fouling.................................................................... 167
INDEX G
Page
Germination ....................................................... 41-42 effects on coconut kernel ....................... 30, 33 H
Page
Harvest ................................................................ 52-53 harvesting by climbing ..................................53 harvesting by monkeys ..................................53 harvesting by pole..........................................53 Homogenization ............................................111-112 Humidity for coconut growth .................................45 L
Page
Lauric acid............................................... 21-22, 32-33 Life cycle ...................................................................40 Lipid oxidation .........................................................88 Lipolysis ............................................................. 88, 94 Long life products .........................................113-128 M
Page
Magnesium in coconut kernel ............................................36 in coconut water ...................................... 26, 77 water quality content............................. 97, 174 Maillard reaction ......................................................79 Maturity .............................................................. 52, 82 Medium chain triglycerides (MCTs) .............. 21, 32 Microbiology of coconut milk and cream ...................... 93-94 of coconut water ....................................... 83-84 Minerals.............................................................. 29, 36 also see calcium, chlorine, electrolytes, magnesium and sodium N
Page
Nata de coco ............................................................71 O
Page
Oil content of coconut kernel................................30-31, 33 of coconut milk and cream ...................... 86-87 of dessicated coconut ....................................70 Optical density see turbidity Oxidation see browning, pinking, lipid oxidation and rancidity Oxygen exposure ............................................. 82, 92
P
Page
Packages ................................................................ 143 Bottles............................................................ 147 Cans ............................................................... 149 Carton based ........................................ 144-146 Flexible pouches .......................................... 149 Packaging Aseptic packaging ....................................... 143 Design innovation ................................ 150-152 Role of packaging ........................................ 138 Selection of packaging........................ 140-142 Paring........................................................................ 55 Peroxidase see enzymes Pasteurization................................................. 130-131 Pests ............................................................. 47-48, 50 pH ........................................................... 29, 91, 156 Phenolic content...................................................... 29 of coconut kernel ........................................... 36 of coconut oil .................................................. 67 of coconut water............................................. 77 Physicochemical properties see chemistry see composition Pinking ............................................................. 80, 159 Plantation see Agroecology see Agronomic characteristics see Varieties Planting systems ...................................................... 46 Polyphenol oxidase see enzymes Polyphenols ..........................................28, 29, 78, 82 also see phenolic content Post-harvest ....................................................... 54-56 Potassium in coconut kernel............................................ 36 in coconut water................................. 26, 76-77 in fertilizer........................................................ 46 Product quality....................................................... 128 Production of coconut and coconut products .... 59 of coconut ................................................ 12-13 of coconut flour .............................................. 68 of coconut milk and cream ..................... 62-63 of coconut milk beverages............................ 64 of coconut milk powder ................................ 68 of coconut oil ............................................ 64-65 refined, bleached, deodorized (RBD) coconut oil.................................................. 66 virgin coconut oil ....................................... 67 of coconut water....................................... 58-60 of desiccated coconut ............................ 69-70 of nata de coco ...............................................71 Propagation........................................................ 41-44 Protein see amino acids
Q
Page
Quality control ...............................................154-155 Quality parameters ............................................... 155 colour ............................................................ 158 dry matter or total solids............................. 155 free fatty acids .............................................. 160 microbiological testing ............................... 156 optical density or turbidity ......................... 159 pH .............................................................. 156 sulphite ......................................................... 157 titratable acidity ........................................... 156 total soluble solids....................................... 155 viscosity.................................................110, 160
T
Page
Thermal impact............................................... 82, 123 Total solids ............................................................. 155 Transportation .......................................... 54, 60, 102 Turbidity .................................................... 78, 81, 159 U
Page
Ultra-high temperature (UHT)...................... 122-128 Ultrapasteurization ........................................ 131-133 V
Page
Rainfall for coconut growth ....................................44 Rancidity ...................................................................78 Recombination ........................................................96 of coconut milk products.......................99-101 of coconut water .......................................... 101 Rehydration of the body ................................... 16-19 Rheology see viscosity
Varieties of coconuts................................... 25, 38-39 Virgin coconut oil (VCO)...................................65, 67 Viscosity .................................................................. 105 flow behaviour models ................................ 109 taking measurements .................................. 110 types of flow.................................................. 106 Vitamin C see Ascorbic acid Vitamins .................................................................... 28 in coconut kernel............................................ 35 in coconut water............................................. 28
S
W
R
Page
Page
Separation of coconut milk and cream...................... 89-91 of coconut water .............................................60 to produce coconut oil ..................................67 Shelf life .................................................. 81, 114, 119 accelerated shelf life ............................161-164 extended shelf life ................................131-135 role of packaging ........................................ 138 Sodium in coconut kernel ............................................36 in coconut water ...................................... 26, 77 in fertilizer .................................................. 45-46 water quality parameter.................................97 Soil for coconut growth...............................44-45, 47 Stabilizers...................................................91, 93, 111 Sterilization during cleaning of equipment ................... 173 of coconut liquid products .. 115-117,120-128 of packaging .........................................138-140 Storage of coconut liquid products.. 82, 102, 133, 142 of coconut seed nuts ..................................... 42 of coconuts...................................................... 81 Sulphite test ........................................................... 157
Page
Water quality................................................... 97, 174 Y
Page
Yield of coconut palms............................................ 46 of extraction of coconut milk and cream................. 63-64 of coconut oil ............................................. 66
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