effectiveness of guava leaves extract as a preservative for vegetables and fruits

“THE EFFECTIVENESS

OF GUAVA LEAVES EXTRACT AS A NATURAL PRESERVATIVE FOR VEGETABLES AND FRUITS”

Science Investigatory Project Presented to

Mrs. Josephine Impe Science 8 Teacher Napnapan National High School Tigbauan, Iloilo

Stephen T. To-ong 8-Ruby 2013-2014

STEPHEN T. TO-ONG 8-RUBY

1

Acknowledgment

The researcher would like to extend his sincere thanks and appreciation to the following people who have contributed, in one way or another, to the realization of this study. Mr. Paul T. Tejero, for the assistance and valuable suggestions, conceptualization, editing the study, helping the researcher for the study, and for the invaluable tips to improve the quality of the research study; Mrs. Josephine Impe, research adviser, for the encouragement and support to the completion of the study. Also, for the assistance and valuable suggestions and for the invaluable tips to improve the quality of the research study; To-ong and Tejero families, the wind beneath my wings as I reach my goals in life, for the unconditional love and prayers, for understanding, and moral support, despite of the challenges that come along; Most of all, to Almighty God, for giving the researcher the courage, knowledge, guidance, love and blessings. Stephen T. To-ong


2

Table of Contents Page Title Page Acknowledgment Chapter 1

Problem & Background of the Study………………………………… Study………………………………… Introduction……………………………………………………………… Statement of the Problem……………………………………………. Problem ……………………………………………. Hypothesis………………………………………… Hypothesis…………… ……………………………….…………………… ….…………………… Objectives of the Study……………………………………………. Study……………………………………………. Scope and Limitations……………… Limitations…………………………………………… …………………………….. Definition of Terms ……………………………………………. Significance of the study……………………………………………. study…………………………………………….

2

Review of Related Literature Related Literature Related Studies

3

Methods of Research and Procedure Method of Research Methodology

4

Presentation, Analysis & Interpretation of Data Findings


3

Analysis of Data 5

Summary of Findings, Conclusions & Recommendations Summary of Findings Conclusions Recommendations

References


4

List of Tables Table 1

Page Images of the Different Groups of Bananas in a Given Period of time…………………………………………………………… time……………………………………………………………

2

Scores of 20 Respondents of the Natural and Commercial Preservative in Terms of Effectivity, Eye Appeal and Odor ……………………………………………………………………….. ………………………………………………………………………..

3

Scores of 20 Respondents on the Secondary Evaluation of Guava Leaves

4

Extract as Preservative……………………….. Preservative………………………..

Operating Procedure……………………………………………………….. Procedure………………………………………………………..


5

Stephen T. To-ong. FEASIBILITY STUDY OF THE GUAVA LEAVES EXTRACT AS A NATURAL PRESERVATIVE FOR VEGETABLES AND FRUITS. FRUITS . Unpublished Science Investigatory Project (SIP). Napnapan National High School, Tigbauan, Iloilo.

ABSTRACT For generations, people bought, caught, or raised fresh foods and cooked them at home to feed their families every day. From the beginning, people struggled to preserve what they gathered, in order to ensure food reserves during times of scarcity. Vegetables and fruits were also dried or stored below ground in a safe place. Not all things in this world are eternal. In fact, almost everything has its limitation. People will die, plants will wither and even the fruit that we need in our daily diet will undergo the process of spoilage. The spoilage is one of the problems the people are facing nowadays, specifically, the vegetable and fruit vendors, and consumers who don’t have refrigerators at home and cannot afford any commercial preservative, in turn cannot store vegetables and fruits for a long time. Thus, the researcher, being one of those consumers who cannot buy commercial preservatives to preserve the vegetables and fruits, came up with the idea and experiment to produce a home-made, easily available,


6

affordable, easy-to-made, and safe-to-use vegetable and fruit preservative from the guava leaves extract. One-fourth (1/4) kilogram of guava leaves was put into a casserole together with 500 ml water. It was boiled within 30 minutes then the residue was separated from the filtrate which is the final product. The l atter contains essential oil rich in cineol and phytonutrients, such as carotenoids, isoffavonoids and polyphenols (flavonoids) as well as saponins, 4 triterpenic acids (including ascorbic acid or Vitamin C) and tannins existing in aqueous and ethanolic extract. The product was tested in bananas for 12 days (it can be applied or used also to any vegetables or fruits) and the result showed that the constituents of the extract led to it being able to prolong the shelf-life of fruit- banana.


7

“THE EFFECTIVENESS OF GUAVA LEAVES EXTRACT AS A NATURAL PRESERVATIVE FOR VEGETABLES AND FRUITS” FRUITS”

Stephen T. To-ong

CHAPTER I PROBLEM AND BACKGROUND OF THE STUDY This part introduces the study by stating the objectives of the study, the problems to be answered, the significance of the study to certain populations, the hypothesis to be proved and terms to be defined.

Introduction Since the beginning of time, people have looked for ways to preserve food. Without preservation, all foods will spoil in time. Pests, chemicals, and micro-organisms are the great agents most often responsible for food spoilage. They can be found everywhere that vegetables and fruits are grown, harvested and stored. However, spoilage may occur before changes in the flavor or odor can be noticed. For those who cannot afford to buy preservatives for the food,


8

the researcher have studied guava as a natural preservative to solve the main problem in preserving foods. Guava (Psidium Guajava Linn), a member of family Myrtaceae, is a plant with several medicinal uses which are known and recognized worldwide, and studies and researches are still being conducted to discover its other uses. Guava is a very good source of vitamins, fibres’ as fibres’ as well as minerals. Being rich in Vitamin C; guava is effective in treating male infertility caused by sperm clumping, adhesion and other abnormalities. It has been associated with healing of wounds, when applied externally. Also, guava has general haemostatic properties and can be used for treating bleeding nose, gums and minor internal haemorrhaging. Guava, having high content of roughage, no cholesterol & less digestible carbohydrates, is good for those trying to lose weight. Researches have shown that guava is pretty effective in preventing cancer and even heart diseases in people. Guava is also effective in lowering cholesterol and blood sugar levels due to the presence of complex carbohydrates and dietary fibres’. fibres’. Guava leaves help cure dysentery, by inhibiting microbial growth and removing extra mucus from the intestines. Guava is one of the richest sources of


9

dietary fiber and thus, strengthens and tones up the digestive system and even disinfects the same. It is also also good for those suffering from constipation. Guavas can improve the texture of skin and help avoid skin problems. For the purpose, you can either eat it raw or make wash your skin with a decoction of its immature fruits and leaves, which is also known to bring relief in cough c ough and cold. The presence of ascorbic acid and other phytonutrients, such as carotenoids, isoffavonoids and polyphenols (quercetin in particular), in guava leaves has led to it being an effective antioxidant. Thus, help the body in combating free radicals produced during metabolism and aids in preventing age-related age-related chronic diseases, such as Alzheimer’s, cataract and rheumatoid arthritis. Much of the therapeutic activity of guava is attributed to the flavonoids of the leaves which also demonstrate antibacterial and antioxidant effect together with Vitamin C and other phytonutrients. Since certain antibacterial and antioxidants nowadays are being used in industry as food preservatives, guava leaves may be a source of preservative for fruits like bananas. Some of the commercial food preservatives available today contain harmful substances which may not be safe for human health. Due to this, researcher is now searching for alternative preservatives which are cheaper and safer to use. Guava leaves may be the answer.


10

Statement of the Problem The study was conducted to determine the effect of guava leaves l eaves extract in vegetables or fruits like bananas which is the subject of the study. The following questions need to be answered: 1) What are the components of guava leaves extract which have uses and abilities similar to commercial preservatives? 2) How effective is the guava leaves extract in preserving bananas? 3) What makes guava leaves extract different compared to commercial preservatives in terms of: -effectivity

-affordability

-eye appeal

-availability

-odor

-safetiness

4) Is guava leaves extract feasible as a substitute for commercial preservatives?

Hypothesis Is there a significant relationship between guava leaves extract and commercial preservatives in preserving vegetables or fruits like bananas?


11

Objectives of the study 1) General Objective The study aims to lengthen the shelf-life of vegetables or fruits like bananas which is the subject of the study. s tudy. 2) Specific Objective The study was conducted to produce an alternative preservative from guava leaves which is more affordable, more available and safer to use.

Scope and Limitation The study was conducted in Sitio Gines, Barangay Napnapan Sur, Tigbauan, Iloilo which has plenty of guavas and bananas, and during the peak season of the latter. Basically, the study was limited to families and individuals consuming any vegetables or fruits specifically bananas but do not have refrigerators and cannot afford to buy commercial preservative, thus cannot consume bigger mass of any vegetables or fruit specifically bananas. However, it may also be applicable to vendors of any vegetables or fruits specifically bananas who are in the need of a preservative but cannot afford any.


12

Definition of terms BananasBananas- A banana is an edible fruit produced by several kinds of large herbaceous flowering plants plants of the genus Musa. CarotenoidsCarotenoids- are organic are organic pigments pigments that are found in the chloroplasts the chloroplasts and chromoplasts of plants and some other photosynthetic organisms photosynthetic organisms like algae, like algae, some bacteria, some bacteria, and and some fungi. some fungi. Carotenoids Carotenoids can be produced from fats and other basic organic metabolic building blocks by all these organisms. Carotenoids generally cannot be manufactured by species in the animal kingdom so animals obtain carotenoids in their diets, and may employ them in various ways in metabolism. CineolCineol- is a natural organic compound which is a colorless liquid. It is a cyclic ether and a monoterpenoid. Commercial preservativepreservative - are those preservatives which can be bought in the market. DysenteryDysentery- is an inflammatory disorder of the intestine, intestine, especially of the colon, colon, that results in severe diarrhea severe diarrhea containing blood and and mucus in the the feces with fever, with fever,

abdominal pain, pain, and rectal tenesmus (a feeling of incomplete

defecation), caused by any kind of infection.


13

Extract - is a substance made by extracting by extracting a part of a raw a raw material, often material, often by using a solvent a solvent such as ethanol as ethanol or water. Extracts water. Extracts may be sold as tinctures as tinctures or in powder form.

Flavonoids- are Flavonoids- are a class of plant of plant secondary secondary metabolites. Flavonoids metabolites. Flavonoids were referred to as Vitamin P (probably because of the effect they had on the permeability of vascular capillaries) capillaries) from the mid-1930s to early 50s, but the term has since fallen out of use.

FoodFood - material consisting essentially of protein, carbohydrate, and fat used in the to sustain growth, repair, and vital processes and to furnish energy.

GuavaGuava- any of several several tropical American shrubs shrubs or small trees of the myrtle family. It is widely cultivated for its sweet acid yellow or pink fruit.

Guava Leaves Extract - the liquid produced from the guava leaf after it has been boiled.

IsoffavonoidsIsoffavonoids- are a class of flavonoid of flavonoid phenolic compounds. They are biologically active compounds, such as phytoestrogens, as phytoestrogens, produced produced by pea by pea family plants. Isoflavonoids are derived from the flavonoid fl avonoid biosynthesis pathway via liquiritigenin via liquiritigenin or naringenin. naringenin.


14

Natural preservative-it preservative -it is not required that it can be bought in the market. It has no other chemicals mixed not just like commercial preservative. PhotochemicalPhotochemical- The chemistry of the effects of light on chemical c hemical systems. PhytonutrientsPhytonutrients- natural chemicals that are found in a variety of plant foods. PolyphenolsPolyphenols- are a structural class of mainly natural, mainly natural, but but also synthetic also synthetic or semisynthetic, organic semisynthetic, organic chemicals characterized by the presence of large multiples of phenol of phenol structural units. The number and characteristics of these phenol structures underlie the unique physical, chemical, c hemical, and biological (metabolic, toxic, therapeutic, etc.) properties of particular mem bers of the class. They may be broadly classified as phenolic as phenolic acids, flavonoids, acids, flavonoids, stilbenes, stilbenes, and

lignans. PreservativePreservative- is a naturally occurring or synthetically produced substance

that is added to products such as foods, pharmaceuticals, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical undesirable chemical changes. Spoilage Spoilage- is the process in which food deteriorates to the point in which it is not edible to humans or its quality of edibility becomes reduced.


15

VegetablesVegetables- is an edible edible plant or its part, part, intended for cooking or eating raw.

Significance of the Study The study aims to benefit the following populations: To the researcher, this may help him to have the ability to buy bigger mass of any vegetables or fruits like bananas without the need to worry of its shel f-life. To the small farmers and vendors of any vegetables or fruits like bananas, this may be a help for them in maintaining the texture of their products until these were delivered and consumed. To the families without refrigerators and cannot afford commercial preservatives, this may cause them not to buy retail any vegetables or fruits like bananas or that which will be consumed for a short span of time anymore. Instead, they can buy more any vegetables or fruits like bananas which can stay in shelves for longer time. To the entire population, this may be the answer in its search for available, affordable, and safer-to-use preservative.


16

CHAPTER II REVIEW OF RELATED LITERATURE Antioxidant is a type of molecule that neutralizes harmful compounds called free radicals that damage living cells, spoil food, and degrade materials such as rubber, gasoline, and lubricating oils. These work against the molecules that form free radicals by destroying them before they can begin the domino effect that leads to oxidative damage. Although oxygen metabolism is essential to life, the antioxidants diminish excessive activity and damage to the cell. Antioxidants can take the form of enzymes in the body or vitamin supplements. They are routinely added to metals, oils, and other materials to prevent free radical damage. Antioxidants are also used as industrial additives and food preservative. Industrial antioxidants slow or prevent oxidative damage that causes food to spoil, and fats and oil to change color or go rancid. Ascorbic acid or vitamin C and the synthetic antioxidants butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are among the antioxidants used nowadays as food preservative. These antioxidants are added to foodstuffs in concentrations of much less than 1 percent. It was also reported that carotenoids, molecules found in tomatoes, carrots and guavas, have the ability to neutralize harmful compounds such as


17

free radicals that are known to damage cells. Therefore, this compound is now accepted as an antioxidant. However, antibacterial or antimicrobials are chemical compounds used to kill or inhibit the growth of microorganisms. These work against organic compounds produced by bacteria or molds to prevent the damages caused by these. Antibacterial Antibacterial may be classified as bactericidal (killing bacteria) or bacteriostatic (stopping bacterial growth and multiplication). Some types of antibacterial are antiviral, antibody, antitoxin, antispasmodic and antiseptics. Antiseptic, a type of antibacterial, is a physical or chemical agent that prevents putrefaction, infection, and analogous changes in food and living tissue by destroying or arresting the development of microorganisms. In ancient times some antiseptic agents used were heat in cooking; niter, salt, and vinegar in corning and pickling; and wood smoke (containing creosote) in the smoking of meats. Meanwhile, in modern times we have processes like canning, pasteurization, and refrigeration. In 1955, the Food and Drug Administration permitted for the first time the use of an antibiotic in food. The antibiotic chlorotetracycline is used as a preservative for uncooked poultry and is called Acronize. Added to the water in


18

which poultry is chilled after dressing, the antibiotic stops the early growth of bacteria responsible for most food spoilage. Acronize introduces no change in taste, color, or appearance of the poultry. The quantities of antibiotic added are so small that they are destroyed by cooking. Other formulations, adaptable to the red meat and fish industries, are being developed. Nowadays, studies are being conducted by many researchers to discover new scientific uses of many natural sources. Psidium Ps idium Guajava Linn (Myrtaceae) is one of such natural sources which can c an have many potential scientific uses. On 2002, a study regarding on the antimicrobial activity of guava leaves was conducted by Anthony C. Dweck, a chartered chemist and scientist, and a fellow of the Linnean Society. The study showed that the guava leaves contain an essential oil rich in cineol, and 4 triterpenic acids as well as 3 flavonoids, quercetin, its 3-L-4-4-arabinofuranoside (avicularin) and its 3-L-4-pyranoside, components with strong antibacterial action. The leaves were extracted and the product showed in vitro antimicrobial activity against Escherichia coli, Salmonella typhus, Staphylococcus aureus, Proteus mirabilis, and Shigella dycenteria. The tannin in the leaves was capable of these. The flavone derivatives also in guava leaves were reported to inhibit the growth of Staphylococcus aureus.


19

Similarly, a broad spectrum of the antimicrobial activity of guava leaves was proved (Ibrahim Iliya et al., 2010).In the study, the leaves were extracted with hexane, ethyl acetate and methanol which were tested in vitro for vitro for activity against standard strains of microbes and clinical isolates. The

in vitro

antimicrobial screening revealed that the extract inhibited varying activity against

different

microbes

with

zones

of

inhibition-Minimum

Inhibitory

Concentration (MIC), Minimum Bactericidal Concentration (MIB) and Minimum Fungicidal Concentrations (MIF). The highest activity was in MIC of 1.25 mg/mL and MBC of 2.5 mg/mL and none in fungi isolates except the Candida albicans. The activities observed in the study were due to the presence of some secondary metabolites such as tannins, saponins, terpenes and flavonoids which were detected and have previously been reported in the plant.

Photochemical from guava leaves extract has also showed antioxidant activity (Venent Nihorimbere et al., 2004). Dried ground guava leaves were extracted by water and aqueous ethyl alcohol 50% (1:10 ratio), and total phenolic content in the extracts was determined spectrophotometrically. By means of a 2, 2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm, at ambient temperature, the antioxidant activity of lyophilized extracts was determined. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to


20

yellow. The results obtained implied that ascorbic acid, constituent of guava leaves extract, was a substantially powerful antioxidant. This revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

Similarly, tannins from guava leaves extract which exist in aqueous and ethanolic extracts act as antioxidants (Simeray et al., 1982; 1982; Yoshizawa et al., 1987). 1987). It was also reported that the presence of Vitamin C and other phytonutrients, such as carotenoids, isoffavonoids and polyphenols in guava has led to it being a substantially effective antioxidant (Formica and Regelson, 1995).


21

CHAPTER III METHODS OF RESEARCH AND PROCEDURE This chapter offers discussions of the main method of research used in the conduct of the study and the procedures in the conduct of the experiment.

Method of Research The sole purpose of the study is to produce a natural vegetable and fruit preservative from guava leaves that is cheaper, more available and has no side effects to health but is as effective as commercial preservative. The method of research used for the conduct and purpose of this study was experimental method. Any vegetables or fruits may be used as the subject of the study but in this case, the researcher used banana as a subject of the s tudy.

Methodology A) Materials and Equipments ¼ kg guava leaves 500 mL water Cloth Casserole


22

Container (preferably, a sprayer) Bananas (at least 9 pieces; for experimentation) B) Procedures 1) Preparation The things needed-the casserole, ¼ kg guava leaves, 500 mL water, bananas, cloth and container-were washed and placed on a clean table. 2) Formulation One-fourth kilogram of guava leaves was put into the casserole together with 500 mL water. It was boiled for 30 minutes. Then, using the cloth, the residue was separated from the filtrate which is the final product. The product was left to cool for 15 minutes and was poured into the container. 3) General Procedure Using the sprayer, guava leaves extract was sprayed to a group of bananas (at least 3 pieces, for some unavoidable situations). It was left in a place where it is safe and exposed in air together with another group of bananas without any preservative, and a group with commercial


23

preservative. The set-up was observed daily for 12 days and the results were recorded.


24

CHAPTER IV PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA This chapter involves the discussion of results through the analysis and interpretation of data. It also presents all the data gathered from the perception of the respondents on the natural and commercial preservatives in terms of cost, eye appeal, odor, effectivity, availability and effects on health.

Findings Table 1 Images of the Different Groups of Bananas in a Given Period of time Groups of Bananas Period

Without any Preservative

With Natural Preservative

With Commercial Preservative

Day 0


25

Day 6

Day 8

Day 10

Day 12


26

Table 2 Scores of 20 Respondents of the Natural and Commercial Preservative in Terms of Effectivity, Eye Appeal and Odor Sample

Effectivity

Eye Appeal

Odor

Natural

12

13

12

Commercial

8

7

8

Preservative

Table 3 Scores of 20 Respondents on the Secondary Evaluation of Guava Leaves Extract as Preservative Sample

Availability

Cost

Effects on Health

Natural

14

16

18

Commercial

6

4

2

Preservative


27

Analysis of Data Table 1 shows 1 shows that the guava leaves extract is as effective as commercial comm ercial preservative. On the first 6 days of evaluation, all the bananas have almost the same peel color-all are still yellow with dark spots and regions. After 8 and 10 days, these regions turn larger for all the bananas, but the two sets of bananas with preservative have lesser dark regions than the other one. When the bananas were all peeled on Day 12, images show that those without any preservative have been totally spoiled, but still, in the two other groups, bananas are still edible. Table 2 shows 2 shows that most of the respondents chose natural preservative in terms of effectivity and eye appeal. It implies that they perceived that the natural preservative is as effective as the commercial one. Meanwhile, most of them chose the natural one in terms of odor. Table 3 shows 3 shows that the respondents perceived that the natural preservative is more available and affordable than the commercial c ommercial one. Majority of the respondents also trust the natural one when it comes to effects on human health.


28

Table 4 Operating Procedure PROCEDURE

PICTURE

One-fourth kilogram of guava leaves was put into the casserole together with 500 mL water.

Boil for 30 minutes

Using the cloth, the residue was separated from the filtrate which is the final product.

Left the product to cool for at least 15 minutes and pour it into the container.


29

Using the sprayer, spray the guava leaves extract to a group of bananas

Left the banana’s in a place where it is safe and exposed in air

Observe the set-up for 12 days. The result should be recorded daily.


30

CHAPTER V SUMMARY OF FINDINGS, CONCLUSIONS AND RECOMMENDATIONS This section covers the summary of findings and generalizations formed based on the results. Using the findings and conclusions, recommendations were also given.

Summary of Findings The study was conducted to test the feasibility of the guava leaves extract in preserving vegetables and fruits, specifically bananas. The data gathered showed that the flavonoids and other phytonutrients which are found in guava leaves and are also known as antioxidants and antibacterial, have the ability to preserve fruits like bananas. Since it has been found that it is effective, guava leaves extract was compared to commercial preservative in terms of many aspects. The researcher used 20 respondents who are vendors and consumers of bananas, and are aware on some aspects of preservatives.


31

The respondents found that guava leaves extract is as effective as commercial preservatives. They also preferred both in terms of eye appeal. Yet, in terms of odor and availability, guava leaves extract obtained better results. Meanwhile, most of the respondents chose the natural one when it comes to cost. The data also showed that the respondents perceived that guava leaves extract gives no side effect to human health. In this study, it was found out that it should not need to buy commercial preservatives in the local market just to preserve the vegetables and fruits that have in the table for a longer time. What should be needed is just to look for guava (any variety will do) leaves and have with you the natural preservative that you’re looking looking for. Today, we should be more practical, save for money and protect our health. Let ourselves not to be encouraged by advertisements either in radio or TV, because in fact, we don’t really need it much but be wise all the time in all aspects that we need n eed for ourselves. It’s always in the environment, don’t need to go far just look for what you want.

Conclusions Using the results as bases, the subsequent conclusions were drawn: The cineol and phytonutrients, such as carotenoids, isoffavonoids and polyphenols (flavonoids) as well as saponins and Vitamin C found in guava


32

leaves extract make it effective in lengthening the shelf-life of fruits like bananas and thus, it is acceptable as a preservative. It is as effective as commercial preservative but is cheaper, since guava leaves are easily available and the extract is easy to make. It is feasible as a substitute for commercial preservative because aside from the reasons which are already mentioned, it has no adverse effect on human health since it is from natural and fresh leaves, and does not contain any amount of chemical or artificial additives.

Recommendations Based on the foregoing data, here are the recommendations given: Guava leaves extract is recommended for preservative use, especially at home, not only for bananas, but for other vegetables and fruits. For future researchers, further studies can be done to search for other plant alternative containing flavonoids, carotenoids, or those having antioxidant and antibacterial effect such as tomatoes and carrots. Further, there’s a million of topics that can be used by the different plants in the environment. What should need to do is to experiment, study and research. Just like this study, it was just an experimental study in which accidentally gave a good result. Always


33

remember, almost all discoveries by the people are all the result of accidents that even them don’t really expect such much.


34

BIBLIOGRAPHY Abdelrahim, S. I., et al. “ Antimicrobial activity of Psidium guajava

L.”

Fitoterapia 2002; 73(7-8): 713-5.

Arima, H., et al. “Isolation “Isolation of antimicrobial compounds from guava (Psidium guajava L.) and their structural elucidation ”, Biosci. Biotechnol. Biochem.2002; Biochem.2002; 66(8): 1727-30.

Conde Garcia, E. A., et al. “Inotropic “Inotropic effects of extracts of Psidium guajava L. (guava) leaves on the t he guinea pig atrium”, atrium ”, Braz. J. of Med. & Biol. Res. Res . 2003; 36: 661-668.

Garcia, S., et al, “Inhibition “Inhibition of growth, enterotoxin production, and spore formation of Clostridium perfringens by extracts of medicinal plants ”, J. Food Prot. Prot. 2002; 65(10): 1667-9.

Jaiarj, P., et al. “ Anticough and antimicrobial activities of Psidium guajava Linn. Leaf extract”, extract ”, J. J. Ethnopharmacol. Ethnopharmacol. 1999; 67(2): 203-12.

Jimenez-Escrig, Jimenez-Escrig, A., et al. “Guava “Guava fruit (Psidium guajava L.) as a new source of antioxidant dietary dietary fiber ”, J. ”, J. Agric. Food Chem. Chem. 2001; 49(11): 5489-93.


35

Marquina V, Araujo L, Ruz J, Rodriguez-Malaver Rodriguez-Malaver A, Vit P. “Composition “ Composition and antioxidant capacity of the guava (Psidium guajava L.) fruit, pulp and jam ”, Arch Latinoam Nutr . 2008 Mar; 58(1):98-102. PMID: 18589579.

Oh WK, Lee CH, Lee MS, Bae EY, Sohn CB, Oh H, Kim BY, Ahn JS. “ Antidiabetic effects of extracts from Psidium guajava”, guajava ”, J J Ethnopharmacol. Ethnopharmacol. 2005 Jan 15; 96(3):411-5. PMID: 15619559. 17.

Pranee Jaiarj, et al. “ Anticough and antimicrobial activities of Psidium guajava Linn leaf extract”. extract”. Journal Journal of Ethnopharmacology Ethnopharmacology , Volume 67, Issue 2, November 1999, Pages 203-212. doi: 10.1016/S0378-8741(99)00022-7 18.

Qian H, Nihorimbere V. “ Antioxidant power of phytochemicals from Psidium guajava leaf ”, J ”, J Zhejiang Univ Sci. Sci. 2004 Jun; 5(6):676-83. PMID: 15101101.

Xavier Lozoya, et al. “Intestinal “ Intestinal anti-spasmodic effect of a phytodrug of Psidium Guajava folia in the treatment of acute diarrheic disease ”, Journal of Ethnopharmacology,, Volume 83, Issues 1-2, November 2002, Pages 19-24. doi: Ethnopharmacology 10.1016/S0378-8741(02)00185-X 19. Jonny Bowden. The 150 healthiest foods on earth.


36

effectiveness of guava leaves extract as a preservative for vegetables and fruits

Recommend Documents