Guava ( Psidium guajava ) Fruit Phytochemistry and Nutritional Significance
The fruit of guava is very rich in Vitamin C, which is substantially higher than what is found in citrus. It is also a good source of Vitamin A and other important elements. The fruit contains a large amount of citric, lactic, malic, oxalic and acetic acids and a trace amount of formic acid.
The ripe fruit is usually eaten as a dessert. It can also be utilized in many ways for making jellies, jam, paste, juice, baby foods, puree, beverage base, syrup, wine and other processed products. It may be eaten sliced with cream and sugar and as ingredient in cakes and pies. It is also used in dishes like “sinigang”.
Some parts of guava tree have medicinal and commercial usefulness. The bark and leaves are used in childbirth to expel the placenta. The leaves can be made into tea and astringent decoction can cure stomachache and act as vermifuge. When crushed or chewed, it is used for toothache treatment; pounded leaves may also be applied locally for rheumatism; can also be used for dyeing and tanning. The bark is sometimes used in complex cosmetics for hystero-epilepsy. Its wood is moderately strong and durable indoor and useful for handle and in carpentry and turnery.
Supreme – The Supreme varieties from Florida. It is generally high yielding and produces a thick white flesh fruit of good quality for preserving or eating fresh. Fruit shape is ovate with distinct corrugation, 6.3 cm long, 5.5 cm in diameter and weighing 65 grams. The three is moderately prolific and regular bearing. When fully ripe, the fruit is bright yellow in color. The flavor in the inner pulp is sweet but the outer skin is slightly bitter and possesses a distinct strawberry wine odor, which is slightly astringent. It is moderately resistant to anthracnose and fruitfly but susceptible to leaf folder and aphids.
Red Indian Rolfs and Ruby – the fruit is ovate, 6.5 cm long, 5 cm in diameter with thin, smooth, medium green skin, weighing 75 grams. The fruit pulp is about 10 mm deep and red when fully ripe and has less pronounced corrugation. It is large seeded, sparsely populated but very sweet, juicy, crunchy and possesses a strong aroma. The tree is very prolific, regular bearing but easily attack by bats, moderately to anthracnose and oriental fruitfly.
Crosses between Ruby and Supreme – a large, white flesh variety from California, U.S.A.
Seedless variety – this variety has a fleshy layer, thick, that almost no seed cavity remained
Goyena Quezo de Bola (NSIC 02 Gv-01) – this is NSIC guava variety approved in 2002, being a prolific yielder possessing yellowish green color of skin, finely smooth texture with pleasant aroma and weigh 575 g/fruit.
03. Processing and Utilization
Select ripe and sound fruits. Cut into quarters. To 1 part fruits, add 2 parts water. Boil until the fruits are soft. Strain and measure the extract. To every three (3) parts extract, add 1 part sugar. Stir and measure the extract. Cool. To every 15 to 15 liters, add one-tablespoon yeast. Place in demijohns to ferment. This will take from two weeks or longer. When the fermentation is completed, transfer into wine barrels and age for at least one year.
Select equal mixture of green and ripe guavas. Wash and cut into halves or quarters. For every kilo of guavas, add 2 liters of water. Boil in enamel or stainless steel basin for 30 minutes. Strain thru a cheesecloth bag. Crush the pulp and boil again, using 1-½ liters of water. Strain and combine the 2 extracts. Measure. To every cup of the extract, add ¾ cup of sugar and 1 tablespoon of calamansi juice. Boil once to dissolve sugar and strain. Cook over strong fire until the temperature reaches 107o-108o until a soft ball is formed when the jelly is dropped in a cup of water. Pour in sterilized dry glass jars.
BROWN, E.H. Useful Plants of the Philippines. Volume 3. pp. 152-155
CORONEL, R. E. 1983. Promising Fruits of the Philippines. College of Agriculture. U.P. Los Baños. Pp. 204-231
RANTUGAN, H. 1986. Guava In: Plant Industry Guide, Bureau of Plant Industry. 13 p.
SUDIARTO and MIEN A. RIFAI. 1992 In: PROSEA Edible Fruits and Nuts. E., Verheigand and R. Colonel (Editors). Bogor, Indonesia. Pp 266-272
CENDANA, S., M. GABRIEL and E. MAGALLONA. 1984. Insect Pests of Fruits Plants in the Philippines, UPLB, College, Laguna 86 p.
04 Nutritional Importance of Guava
Quercetin is considered as most active antioxidant in the guava leaves and is responsible for its spasmolytic activity.
It is well known that guava is frequently employed in numerous parts of the world for the cure of a lot of sickness like diarrhea reducing fever, dysentery, gastroenteritis, hypertension, diabetes, caries, pain relief and wounds.
Guava leaf’s extract doses can reduce the amount of cough due to its anti-cough activity. Aqueous, chloroform and methanol extract of leaves can reduce the growth of different bacteria.
Guava leaves have high antibacterial activity in extracts that can inhibit the growth of S. aureus . Plant leaf and bark methanolic extracts of P. guajava have high antimicrobial activity. These extracts can inhibit the Bacillus and Salmonella bacteria . Methanolic extract of guava contains a remarkable antimicrobial activity. Species of Bacillus and Salmonella bacteria can be controlled by these extracts.
Guava leaves have quercetin-3-arabinoside and quercetin which can be isolated from leaves. Its leaves contain a compound which has morphine like action. It controls the muscular tone. Quercetin repressed intestinal contraction encouraged by enhanced absorption of calcium. Quercetin has a strong effect on ileum. It is thought that quercetin in guava leaf are responsible for its spasmolytic activity. Guava has high cytotoxicity . Guava can be used to treat the diarrhea caused by the E. coli or S. aureus toxins.
Extract of guava in ethyl acetate can stop the germ infection and thymus production. It can act as anti-viral agent. It can enhance the mRNA expression. Guava can alter the heme oxygenase-1 protein’s work. And due to this reason, it can be used as anti-inflammatory agent for skin. Extract of guava in ethanol inhibit the lipopolysaccharide from manufacturing of nitric oxide. It suppresses the expression of E2. In this way it works as anti-inflammatory agent .
Guava contains high amount of antioxidants and anti-providing nutrients which are essential not only for life but also help to control the free radical activities. It also have a variety of phytochemicals which are beneficial for human health like diabetes, obesity and high blood pressure. There are two common methods by which antioxidants neutralize free radicals that is DPPH and FRAP assay. Extracts of guava in water and organic solvents have a large quantity of antioxidants which can stop the oxidation reaction. The concentration of these compounds become high with the increase in concentration .
Pink guava also has a high antioxidant activity
Guava is highly rich in antioxidants (protocatechuic acid, quercetin, ferulic acid, ascorbic acid, quercetin, gallic acid and caffeic acid ) which are helpful in decreasing the incidences of degenerative diseases such as brain dysfunction, inflammation, heart disease, cancer, arteriosclerosis and arthritis.
Guava extracts in organic solvent influence the sperm production. It can increase sperm concentration due to the presence of antioxidants. An ethanolic extract can increase sperm quality and quantity. So, it can be used for the treatment of infertile males.