Study of presence of
Oxalate ions In
Guava Fruit At different stages of ripening
Made By:
Mahak Shah XII-A
CERTIFICATE This is certified to be bonafide work of the MAHAK SHAH of Class XII B in the CHEMISTRY LABORATORY during academic year 2012-2013.
Teacher In-charge Examiner’s Signature Signature Date………………
Principal
INDEX S.No. 1. 2. 3. 4. 5. 6. 7. 8. 9.
Topic Acknowledgement Introduction Plant Chemicals Oxalic Acid Experiment Observations Calculations Conclusion Bibliography
Page 4 5 6 8 9 11 12 13 14
ACKNOWLEDGEMENT I would like to express my sincere gratitude to Mrs. USHARANI MAM for the valuable guidance and help
provided by her for undertaking and completing this project. I would also like to thank my PARENTS for providing me the material and help in completing this project.
INTRODUCTION Family: Myrtaceae Genus: Psidium Species: guajava Common names: Guava, goiaba, guayaba, djamboe, djambu, goavier, gouyave, goyave, goyavier, perala, bayawas, dipajaya jambu, petokal, tokal, guave, guavenbaum, guayave, banjiro, goiabeiro, guayabo, guyaba, goeajaaba, guave, goejaba, kuawa, abas, jambu batu, bayabas, pichi, posh, enandi Part Used: Fruit, leaf, bark Guava is a common shade tree or shrub in dooryard gardens in the tropics. It provides shade while the guava fruits are eaten fresh and made into drinks, ice cream, and preserves. In the richness of the Amazon, guava fruits often grow well beyond the size of tennis balls on well-branched trees or shrubs reaching up to 20 m high. Cultivated varieties average about 10 meters in height and produce lemon-sized fruits. The tree is easily identified by its distinctive thin, smooth, copper-colored bark that flakes off, showing a greenish layer beneath. Guava fruit today is considered minor in terms of commercial world trade but is widely grown in the tropics, enriching the diet of hundreds of millions of people in the tropics of the world. Guava has spread widely throughout the tropics because it thrives in a variety of soils, propagates easily, and bears fruit relatively quickly. The fruits contain numerous seeds
that can produce a mature fruit-bearing plant within four years.
PLANT CHEMICALS Guava is rich in tannins, phenols, triterpenes, flavonoids, essential oils, saponins, carotenoids, lectins, vitamins, fiber and fatty acids. Guava fruit is higher in vitamin C than citrus (80 mg of vitamin C in 100 g of fruit) and contains appreciable amounts of vitamin A as well. Guava fruits are also a good source of pectin - a dietary fiber. The leaves of guava are rich in flavonoids, in particular, quercetin. Much of guava's therapeutic activity is attributed to these flavonoids. The flavonoids have demonstrated antibacterial activity. Quercetin is thought to contribute to the antidiarrhea effect of guava; it is able to relax intestinal smooth muscle and inhibit bowel contractions. In addition, other flavonoids and triterpenes in guava leaves show antispasmodic activity. Guava also has antioxidant properties, which is attributed to the polyphenols found in the leaves. Guava's main plant chemicals include: alanine, alphahumulene, alpha-hydroxyursolic acid, alpha-linolenic acid, alpha-selinene, amritoside, araban, arabinose, arabopyranosides, arjunolic acid, aromadendrene, ascorbic acid, ascorbigen, asiatic acid, aspartic acid, avicularin, benzaldehyde, butanal, carotenoids, caryophyllene, catechol-tannins, crataegolic acid, Dgalactose, D-galacturonic acid, ellagic acid, ethyl octanoate, essential oils, flavonoids, gallic acid, glutamic acid, goreishic acid, guafine, guavacoumaric acid, guaijavarin, guajiverine, guajivolic acid, guajavolide, guavenoic acid, guajavanoic acid, histidine, hyperin, ilelatifol D, isoneriucoumaric acid, isoquercetin, jacoumaric acid, lectins, leucocyanidins,
limonene, linoleic acid, linolenic acid, lysine, mecocyanin, myricetin, myristic acid, nerolidiol, obtusinin, octanol, oleanolic acid, oleic acid, oxalic acid, palmitic acid, palmitoleic acid, pectin, polyphenols, psidiolic acid, quercetin, quercitrin, serine, sesquiguavene, tannins, terpenes, and ursolic acid.
GUAVA PLANT SUMMARY Main Preparation Method: decoction Main Actions (in order): antidysenteric, antiseptic, antibacterial, antispasmodic, cardiotonic (tones, balances, strengthens the heart) Main Uses: 1. for dysentery (bacterial and amebic), diarrhea, colic, and infantile rotavirus enteritis 2. as a broad-spectrum antimicrobial for internal and external bacterial, fungal, candidal, and amebic infections 3. to tone, balance, protect and strengthen the heart (and for arrhythmia and some heart diseases) 4. as a cough suppressant, analgesic (pain-reliever), and febrifuge (reduces fever) for colds, flu, sore throat, etc 5. as a topical remedy for ear and eye infections Properties/Actions Documented by Research: amebicide, analgesic (pain-reliever), antibacterial, anticandidal, antidysenteric, antifungal, antimalarial, antioxidant, antispasmodic, antiulcerous, cardiodepressant, cardiotonic (tones, balances, strengthens the heart), central nervous system depressant, cough suppressant, gastrototonic (tones, balances, strengthens the gastric tract), hypotensive (lowers blood pressure), sedative, vasoconstrictor Other Properties/Actions Documented by Traditional Use: anti-anxiety, anticonvulsant, antiseptic, astringent, blood cleanser, digestive stimulant, menstrual stimulant, nervine (balances/calms nerves), vermifuge (expels worms) Cautions: It has a cardiac depressant effect and is contraindicated in some heart conditions.
OXALIC ACID Oxalic acid is the chemical compound formula H2C2O4. This dicarboxylic acid is better described with the formula HO2CCO2H. It is a relatively strong organic acid, being about 10,000 times stronger than acetic acid. The dianion, known as oxalate, is also a reducing agent and a ligand in coordination chemistry. Oxalic acid and oxalates are abundantly present in many plants, most notably in sour grass, and sorrel (including Oxalis), roots and leaves of rhubarb and buckwheat. At high concentrations, it is a dangerous poison, but such immediately toxic levels are not found in foodstuffs but rather in manufactures, such as some bleaches, some anti-rust products, and some metal cleaners (among other things). It is also a naturally occurring component of plants, and is found in relatively high levels in dark-green leafy foods In the human body, ingested oxalic acid is not a useful nutrient; so, like all such unneeded components of diet, it is processed by the body to a convenient form and that byproduct is then excreted--in this case, in the urine. In the course of being processed by the body, oxalic acid combines with other substances to form various salts, called oxalates; usually, those salts are in solution, but in high concentration some may precipitate out in crystalline form. Such tiny crystals can cause damage to human tissue, especially to the stomach, the kidneys, and the bladder. It is commonly believed that oxalates
contribute to the formation of kidney and bladder stones; one common nutrient with which oxalic acid combines is calcium, making the salt calcium oxalate, and calcium oxalate is found in kidney stones.
To study the presence of Oxalate Ion content in Guava Fruit at different stages of ripening
Requirements: 100 ml measuring flask, pestle and mortar, beaker, titration flask, funnel, burette, weight box, pipette, filter paper, dilute H2SO4, KMnO4, and guava fruits at different stages of ripening. Theory: Oxalate ions are extracted from the fruit by boiling pulp with dil. H2SO4. Then Oxalate ions are estimated volumetrically by titrating the solution with standard KMnO4 solution. End Point: Appearance of permanent pink colour. Procedure: 1. 50.0g of fresh guava was weighed and crushed to a fine pulp using pestle-mortar. 2. The crushed pulp was transferred to a beaker and about 50ml dil. H2SO4 was added. The contents were boiled for about 10 minutes.
3. The contents were filtered and cooled in 100ml measuring flask. The volume was made up to 100ml by adding distilled water. 4. 20ml of this solution was taken into a titerating flask and 20ml of dil. H2SO4 was added to it. The mixture was heated to about 60°C and titerated against the standard KMnO4 solution taken in a burette 5. The process was repeated with different samples of guava.
Observations: Weight of guava taken
= 50.0 g
Volume of guava extract taken Normality of KMnO4 solution
= 20.0 ml =
Burette readings Initial
Final
Fresh
0
50
Concordant volume of KMnO4 Solution used 50
1 day old 2 day old 3 day old
0 0 0
30 15 9
30 15 9
Guava extract from
Calculations N1V1 = N2V2 (guava extract) (KMnO4 solution) N1 x 20 = xV ∴ Normality of oxalate, N1 = Strength of oxalate = Normality x Eq. mass of oxalate ion =
extract.
Guava extract from Fresh 1 day old 2 day old 3 day old
x 44 g/litre of the diluted
Strength of oxalate ion (g/litre) 5.5 3.3 1.65 0.99
Conclusion Oxalic acid and oxalates are abundantly present in many plants, most notably in sour grass, and sorrel (including Oxalis), roots and leaves of rhubarb and buckwheat. After doing this experiment we can conclude that unripe guava has a high content of Oxalate ions. The concentration of oxalate ions decreases with the ripening of fruit.
BIBLIOGRAPHY In order to complete this project, I took help from: My chemistry teacher Comprehensive Practical Chemistry (Lab Manual) of Laxmi Publication Different internet sites: www.google.com www.rain-tree.com www.wikipedia.com
