INTRODUCTION
GUAVA
Guava
(gwa:və) is a common tropical fruit cultivated in many tropical and subtropical
regions. The common guava Psidium guajava (lemon guava, apple guava) is a small
tree in the myrtle family (Myrtaceae), native to Mexico, Central America, the
Caribbean and northern South America.
The name guava is also given to some other species
in the genus Psidium such as strawberry guava (Psidium cattleyanum) and to the
pineapple guava, Feijoa sellowiana. In 2019, 55 million tonnes of guavas were
produced worldwide, led by India accounting for 45% of the total. Botanically,
guavas are berries.
Guava fruits, usually 4 to 12 centimetres (1+1⁄2 to
4+1⁄2 in) long, are round or oval depending on the species. They have a
pronounced and typical fragrance, similar to lemon rind but less sharp.
The outer skin may be rough, often with a bitter
taste, or soft and sweet. Varying between species, the skin can be any
thickness and is usually green before maturity, but may be yellow, maroon, or
green when ripe.
The pulp inside may be sweet or sour and off-white
("white" guavas) to deep pink ("red" guavas).The seeds in
the central pulp vary in number and hardness, depending on the species.
Culinary uses
In Mexico and other Latin American countries, the popular
beverage Agua fresca is often made with guava. The entire fruit is a key
ingredient in this punch, and the juice is often used in culinary sauces (hot
or cold), ales, candies, dried snacks, fruit bars, and desserts, or dipped in
chamoy.
Because of its high level of pectin, guavas are
extensively used to make candies, preserves, jellies, jams, and marmalades
(such as Brazilian goiabada, Colombian and Venezuelan bocadillo), and as a marmalade
jam served on toast. Red guavas can be used as the base of salted products such
as sauces, substituting for tomatoes, especially to minimize the acidity. A
drink may be made from an infusion of guava fruits and leaves, which in Brazil
is called chá-de-goiabeira, i.e., "tea" of guava tree leaves,
considered medicinal.
Main
Constituents
Nutrients Guavas are rich in dietary fiber and
vitamin C, with moderate levels of folic acid. Low in food energy per typical
serving, and with few essential nutrients, a single common guava (P. guajava) fruit
contains 257% of the Daily Value (DV) for vitamin C. Nutrient content varies
across guava cultivars.
Although the strawberry guava (P. littorale var.
cattleianum) has only 39% of the vitamin C in common varieties, its content in
a 100 gram serving (90 mg) still provides 100% of the DV.
Phytochemicals
Guava leaves contain both carotenoids and polyphenols
like (+)-gallocatechin and leucocyanidin. As some of these phytochemicals
produce the fruit skin and flesh color, guavas that are red-orange tend to have
more polyphenol and carotenoid content than yellow-green ones.
Guava seed oil Guava seed oil, which may be used for
culinary or cosmetics products, is a source of beta carotene, vitamin A,
vitamin C, copper, zinc and selenium, and is particularly rich in linoleic
acid.
The composition of fatty acids in guava seed oil
are: Lauric acid < 1.5%; Myristic acid < 1.0%; Palmitic acid:
8-10%; Stearic acid: 5-7%; Oleic acid: 8-12%; Linoleic acid: 65-75%; Saturated
fats: total 14%; and Unsaturated fats: total 86%.
Varieties of
commercially grown guavas in India
ü Allahabad Safeda
ü Sardar (Lucknow-49)
ü Arka Mridula
ü Lalit
ü Shweta
ü Allahabad Surkha
ü Kohir Safeda
ü Arka Amulya
ü Arka Kiran
Varieties of
commercially grown guavas in Karnataka
ü Chittidar
ü Hafsi
ü Navalur
ü Red flesh
ü Apple colour
ü Pant Prabhat
ü Hisar Safeda
ü Benaras
ü Hisar Surkha
ü Smooth green
ü Nasik
Varieties
Anakapalli,
Banarasi, Bangalore, Chittidar, Hafshi, Nagpur Seedless, Smooth Green.
The
principal pre-harvest strategy and post-harvest technology for reducing
the
post-harvest losses are as under :
i)
Pre-harvest treatment.
ii)
Correct stage of harvesting
iii)
Proper harvesting method
iv)
Proper curing
v)
Washing, cleaning and grading
vi)
Scientific packing
vii)
Pre-cooling
viii)
Cold storage
ix)
Suitable means of transport and
x)
Efficient marketing.
GUAVA FRUIT-PROCESSING
TECHNOLOGIES PROPOSED PRODUCTS
Dehydrated
products
Guava powder
is obtained by dehydration process which is an efficient alternative for
storage of fruit, because the reduction of water activity is related to the decline
of chemical and enzymatic reactions responsible for the deterioration of foods.
Dehydration
process is relied on extraction of water contained in foods up to a minimal
level which is enough to their conservation for long time. Two food products
(powders) were obtained by hot air drying or lyophilisation methods on the
whole guava fruit.
Instant guava-drink-powder
Samples are obtained by dehydrating the concentrated guava juice using
different drying techniques. Dehydration of guava juice into powdered particles
gives a considerable reduction in volume and is an effective method of
prolonging the shelf life. Studies
indicated
that freeze dried product had superior sensory and nutritional qualities,
though spray dried powder was stable and highly economical to prepare free
flowing guava powder having good stability.
Because
of its high level of pectin, guavas are extensively used to make candies,
preserves, jellies, jams, and marmalades (such as Brazilian goiabada, Colombian
and Venezuelan bocadillo), and as a marmalade jam served on toast. Red guavas
can be used as the base of salted products such as sauces, substituting for
tomatoes, especially to minimize the acidity. A drink may be made from an infusion
of guava fruits and leaves, which in Brazil is called chá-de-goiabeira, i.e.,
"tea" of guava tree leaves, considered medicinal
Although the strawberry guava (P. littorale var.
cattleianum) has only 39% of the vitamin C in common varieties, its content in
a 100 gram serving (90 mg) still provides 100% of the DV.
Low
caloric sweetened dehydrated guava slices is an intermediate moisture candy
type product and is a readymade best food for diet conscious people of all ages
and especially for diabetic patients. Samples treated with chemical
preservatives found to have negligible microbial population throughout storage.
Studies showed that guava slices treated with non-nutritive sweeteners were leathery
in appearance due to severe loss of moisture. Maximum overall acceptability was
found in the slices treated with potassium metabisulphite and ascorbic acid.
Guava pulp
Guava pulp as such and in combination with other fruit pulp by blending could
be utilized as a base for preparing different products. Guava pulp was prepared
from guava cultivars - Allahabad Safeda, Lucknow-49, Apple color, chittidar and
Red Fleshed.
Puree,
juice and nectar Fruit processing into purée and juice production are the
most important technologies. Preservation of characteristic nutrients, taste,
flavor as well as color, long shelf-life, easy handling, and convenience, make
juice a valuable and attractive product for both customers and the food
industry. Guava puree is processed by juice processing plants and then frozen until
supplied to the food company for manufacture into various juice blends. However,
pasteurized guava puree undergoes deterioration during storage at frozen
temperatures, resulting in development of off-flavor and decreased sensory
quality of guava juice.
Jam, jelly and preserve
Guava jelly is a sweet, apparent, semisolid, a bit resilient spread or preserve
made from fruit juice and sugar boiled to a thick consistency. Storage of
jellies for nine months at room temperature (23-30°C) and relative humidity 80
to 85% is possible. Color and fla1vor will be acceptable up to 210 days but after
which the color and flavor of jellies will change due to fungal growth and
incipient spoilage.
Guava preserves
These are the result of the appropriate processing of the edible parts, with
added sugars, water, pectin (0.5 to 1.5%), pH adjuster (3 to 3.4), besides other
ingredients and permitted additives until reaching adequate consistency,
assuring product stability. After the processing, the preserves should be
packaged properly and stored under environmental conditions.
Guava jam
or preserves should have the colour characteristic of the product, varying from
yellowish red to brownish red, odour and characteristic flavour reminiscent of
guava and a gelatinous and solid appearance,allowing cutting.
Guava leathers
Guava leather is prepared by dehydrating fruit puree into a leathery sheet.
Leathers can be consumed as a confection or cooked to give a sauce. There is a
dearth of information on the chemical and organoleptic properties of guava
leathers in the tropics. Higher protein and fat content was found in guava
leather.
Canned slices
Guava in syrup is the product that maintains the original shape and appearance
of the fruit. Such a process consists of soaking the fruit in syrup at high
temperatures for a pre-determined period. The high sugar concentration of the
syrup reduces the water activity (Aw), enhancing product shelf-life.
Minimal processing
The minimal processing of fruits is defined as the process that eliminates non-edible
parts, such as rinds, stems and seeds, followed by cutting, washing, classification,
sanitization, centrifugation, packaging and storage, possibly including low
levels of irradiation and whitening, making them ready-to-eat without losing
their freshness, with good quality and degree of sanitization.
There is a dearth of information on the chemical and organoleptic properties of guava leathers in the tropics. Higher protein and fat content was found in guava leather.
Alcoholic beverages Guava
wine may prove to be a quality wine with alcohol (stimulant) and high contents
of phenols and ascorbic acid (antioxidants) besides increasing the economic
status of Indian farmers especially
during period of glut. The chaptalized juice (“must”) is treated with pectinase
or a combination of enzymes and
fermented with traditional yeasts at a temperature range of 22 to 30°C and inoculum size of 6 to 11% (v/v).
Ageing and racking of guava wine improves the organoleptic and sensory characteristics of wine.
Though
India is the largest producer of Guavas worldwide, our export ranking is quite
low due to poor pre and post-harvesting procedures. Knowledge sharing about
best post harvesting, storage,
packaging
and delivery of the graded goods is need of the hour. Horticulture department
can
•
facilitate in this regard.
•
Compared to other states, Karnataka falls behind in production of this fruit
though we have the required ecological conditions for the crop. Handholding and
guidance from concerned authorities will improvise our ranks nationally.
•
Farmers need to be educated about export requirements and international quality
standards of the fruit to curb the dominance of middlemen.
•
Most modern pack house facilities need to be created to facilitate guava
exports from Karnataka. It is suggested that training to packhouse workers
about post-harvest handling technology and also about international quality
standards must be imparted by Agriculture and Horticulture departments.
Regulators and
Service providers
Responsibility
Matrix
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