Kingdom: Plantae Magnoliophyta Class: Liliopsida Order: Fabales Family: Fabaceae Genus: Tamarindus
Imli or Tamarind (Tamarindus indica), also called Indian Date, is a large, broad-leaved, tropical tree found in Haryana and other parts of India and Asia. The word Tamarind is from Arabic 'tamar-ul-Hind', meaning, "the date palm of India". Apart from Imli, among its other regional names are ambilis, amli, tintiri tintul, titri, and teteli. The tree can grow up to 25 meters with a spread of 12 m, and stays evergreen in regions without a dry season. Tamarind timber consists of hard, dark red heartwood and softer, yellowish sapwood. The leaves consist of 10 to 18 leaflets. The tree produces brown pod-like fruits, which contain pulp and hard-coated seeds. The seeds can be scarified to enhance germination.
Tamarind is a multipurpose plant. Its leaves, flowers, and even seedlings, make a tasty broth. The foliage is good for cattle fodder. It is also used as mulch for tender plants and it composts into good manure. The pulp of the fruit is used as a spice in Asian cuisine. The pulp of a young fruit is very sour, and hence suitable for main dishes, whereas a ripened fruit is sweeter and can be used in desserts, drinks, or as a snack. The pulp, leaves, and the bark also have medical applications. Due to its denseness and durability, tamarind heartwood can be used in making furniture and wood flooring.
Except for extremely cold tracts, Tamarind grows naturally all over Asia upto an altitude of about 500 m. In the Indian sub-continent, it is grown from Burma to Afghanistan – more so in central and southern India. Tamarind is not so demanding about the quality of soil. It, however, does very well in deep sandy loam soil and tolerates limited salinity. This is a highly sun-loving plant of warm open areas. It likes humid tracts. Annual rainfall of around 70-200 cm is ideal for this tree and draught is injurious. Tamarind being useful as a shady plant, a timber species, etc., it is widely cultivated. The stock is raised in nurseries. Tamarind seeds well and every year. The fruit is dispersed widely because of its taste. Wild animals, especially monkeys, are very helpful in this regard. Once the seed reaches the soil, it is germinates very well.
Tamarind has 1-2 cm thick dark-grey bark with longitudinal fissures. The leaves are pinnate compound with 5-10 cm long rachis. Each leaf has 10-20 pairs of opposite leaflets. The texture is sub-coriaceous and appearance glabrescent. The canopy is beautiful, umbrella like and the foliage dense. Tamarind bears reddish brown inflorescence in sub-terminal racemes during May-June. The fruit pods, 5-8 cm long, 2-4 mm thick, appear during August-September and ripen by March- April.
The tamarind fruit, also called Imli, is the best-known part. A preparation from the seed is useful for sizing cotton, woolens and jute fabrics and dying silk. The fruits, flattish, beanlike, irregularly curved and bulged pods, are borne in great abundance along the new branches and usually vary from 2 to 7 in long and from 3/4 to 1 1/4 in (2-3.2 cm) in diameter. Exceptionally large tamarinds have been found on individual trees. The pods may be cinnamon-brown or grayish-brown externally and, at first, are tender-skinned with green, highly acid flesh and soft, whitish, under-developed seeds. As they mature, the pods fill out somewhat and the juicy, acidulous pulp turns brown or reddish-brown. Thereafter, the skin becomes a brittle, easily-cracked shell and the pulp dehydrates naturally to a sticky paste enclosed by a few coarse strands of fiber extending lengthwise from the stalk. The 1 to 12 fully formed seeds are hard, glossy-brown, squarish in form, 1/8 to 1/2 in (1.1-1.25 cm) in diameter, and each is enclosed in a parchment like membrane.
It is highly wind-resistant, with strong, supple branches, gracefully drooping at the ends, and has dark-gray, rough, fissured bark. The mass of bright-green, fine, feathery foliage is composed of pinnate leaves, 3 to 6 in (7.5-15 cm) in length, each having 10 to 20 pairs of oblong leaflets 1/2 to 1 in (1.25-2.5 cm) long and 1/5 to 1/4 in (5-6 mm) wide, which fold at night. The leaves are normally evergreen but may be shed briefly in very dry areas during the hot season. Inconspicuous, inch-wide flowers, borne in small racemes, are 5-petalled (2 reduced to bristles), yellow with orange or red streaks. The flower buds are distinctly pink due to the outer color of the 4 sepals which are shed when the flower opens.
Cultivation: Nursery-grown trees are usually transplanted during the early rainy season. If kept until the second rainy season, the plants must be cut back and the taproot trimmed. Spacing may be 33 to 65 ft (10-20 m) between trees each way, depending on the fertility of the soil. With sufficient water and regular weeding, the seedlings will reach 2 ft (60 cm) the first year and 4 ft (120 cm) by the second year. In India there are extensive tamarind orchards producing 275,500 tons (250,000 MT) annually. In India, there may be a delay of 10 to 14 years before fruiting. The tree bears abundantly up to an age of 50-60 years or sometimes longer, then productivity declines, though it may live another 150 years.
Harvesting: Tamarinds may be left on the tree for as long as 6 months after maturity so that the moisture content will be reduced to 20% or lower. Fruits for immediate processing are often harvested by pulling the pod away from the stalk which is left with the long, longitudinal fibers attached. In India, harvesters may merely shake the branches to cause mature fruits to fall and they leave the remainder to fall naturally when ripe. Pickers are not allowed to knock the fruits off with poles as this would damage developing leaves and flowers. To keep the fruit intact for marketing fresh, the stalks must be clipped from the branches so as not to damage the shell. A mature tree may annually produce 330 to 500 lbs (150-225 kg) of fruits, of which the pulp may constitute 30 to 55%, the shells and fiber, 11 to 30 %, and the seeds, 33 to 40%.
Preservation: To preserve tamarinds for future use, they may be merely shelled, layered with sugar in boxes or pressed into tight balls and covered with cloth and kept in a cool, dry place. For shipment to processors, tamarinds may be shelled, layered with sugar in barrels and covered with boiling syrup. East Indians shell the fruits and sprinkle them lightly with salt as a preservative. In India, the pulp, with or without seeds and fibers may be mixed with salt (10%), pounded into blocks, wrapped in palm leaf matting, and packed in burlap sacks for marketing. To store for long periods, the blocks of pulp may be first steamed or sun-dried for several days.
Pest control and diseases: One of the major pests of the tamarind tree in India is the Oriental yellow scale, Aonidiella orientalis. Tamarind scale, A. tamarindi, and black, or olive, scale, Saissetia oleae, are also partial to tamarind but of less importance. Butani (1970) lists 8 other scale species that may be found on the tree, the young and adults sucking the sap of buds and flowers and accordingly reducing the crop.
The mealybug, Planococcus lilacinus, is a leading pest of tamarind in India, causing leaf-fall and sometimes shedding of young fruits. Another mealybug, Nipaecoccus viridis, is less of a menace except in South India where it is common on many fruit trees and ornamental plants. Chionaspis acuminata-atricolor and Aspidiotus spp., suck the sap of twigs and branches and the latter also feeds on young fruits. White grubs of Holotrichia insularis may feed on the roots of young seedlings. The nematodes, Xiphinema citri and Longidorus elongatus may affect the roots of older trees. In India, a bacterial leaf-spot may occur. Sooty mold is caused by Meliola tamarindi. Rots attacking the tree include saprot, Xylaria euglossa, brownish saprot, Polyporus calcuttensis, and white rot, Trametes floccosa. The separated pulp has good keeping quality but is subject to various molds in refrigerated storage.
Uses in Cuisine
The food uses of the tamarind are many. The tender, immature, very sour pods are cooked as seasoning with rice, fish and meats in India. The pulp is made into a variety of products. It is an important ingredient in chutneys, curries and sauces, including some brands of Worcestershire and barbecue sauce, and in a special Indian seafood pickle called "tamarind fish". Sugared tamarind pulp is often prepared as a confection. For this purpose, it is desirable to separate the pulp from the seeds without using water. If ripe, fresh, undehydrated tamarinds are available, this may be done by pressing the shelled and de-fibered fruits through a colander while adding powdered sugar to the point where the pulp no longer sticks to the fingers. The seeded pulp is then shaped into balls and coated with powdered sugar.
Formulas for the commercial production of spiced tamarind beverages have been developed by technologists in India. The simplest home method of preparing the ade is to shell the fruits, place 3 or 4 in a bottle of water, let stand for a short time, add a tablespoonful of sugar and shake vigorously. For a richer beverage, a quantity of shelled tamarinds may be covered with a hot sugar syrup and allowed to stand several days (with or without the addition of seasonings such as cloves, cinnamon, allspice, ginger, pepper or lime slices) and finally diluted as desired with ice water and strained.
Young leaves and very young seedlings and flowers are cooked and eaten as greens and in curries in India.
In 1942, two Indian scientists, T. P. Ghose and S. Krishna, announced that the decorticated kernels contained 46 to 48% of a gel-forming substance. Dr. G. R. Savur of the Pectin Manufacturing Company, Bombay, patented a process for the production of a purified product, called "Jellose", "polyose", or "pectin", which has been found superior to fruit pectin in the manufacture of jellies, jams, and marmalades. It can be used in fruit preserving with or without acids and gelatinizes with sugar concentrates even in cold water or milk. It is recommended as a stabilizer in ice cream, mayonnaise and cheese and as an ingredient or agent in a number of pharmaceutical products.
Flowers: The flowers are rated as a good source of nectar for honeybees in South India. The honey is golden-yellow and slightly acid in flavor.
Seeds: The powder made from tamarind kernels has been adopted by the Indian textile industry as 300% more efficient and more economical than cornstarch for sizing and finishing cotton, jute and spun viscose, as well as having other technical advantages. It is commonly used for dressing homemade blankets. Other industrial uses include employment in color printing of textiles, paper sizing, leather treating, the manufacture of a structural plastic, a glue for wood, a stabilizer in bricks, a binder in sawdust briquettes, and a thickener in some explosives. It is exported to Japan, the United States, Canada and the United Kingdom.
Tamarind seeds yield an amber oil useful as an illuminant and as a varnish especially preferred for painting dolls and idols. The oil is said to be palatable and of culinary quality. The tannin-rich seedcoat (testa) is under investigation as having some utility as an adhesive for plywoods and in dyeing and tanning, though it is of inferior quality and gives a red hue to leather.
Wood: Tamarind wood, weighing about 20-25 kg per cubic foot, is somewhat hard to work. It is also not very durable in outdoor structures exposed to weather. The sapwood of the tamarind tree is pale-yellow. The heartwood is rather small, dark purplish-brown, very hard, heavy, strong, durable and insect-resistant. It bends well and takes a good polish and, while hard to work, it is highly prized for furniture, panelling, wheels, axles, gears for mills, ploughs, planking for sides of boats, wells, mallets, knife and tool handles, rice pounders, mortars and pestles. It has at times been sold as "Madeira mahogany". Wide boards are rare, despite the trunk dimensions of old trees, since they tend to become hollow-centered. The wood is valued for fuel, especially for brick kilns, for it gives off an intense heat, and it also yields a charcoal for the manufacture of gun-powder.
Twigs and barks: Tamarind twigs are sometimes used as "chewsticks" and the bark of the tree as a masticatory, alone or in place of lime with betelnut. The bark contains up to 7% tannin and is often employed in tanning hides and in dyeing, and is burned to make an ink. Bark from young trees yields a low-quality fiber used for twine and string. Galls on the young branches are used in tanning.
Lac: The tamarind tree is a host for the lac insect, Kerria lacca, that deposits a resin on the twigs. The lac may be harvested and sold as stick-lac for the production of lacquers and varnish. If it is not seen as a useful byproduct, tamarind growers trim off the resinous twigs and discard them.
Medicinal uses of Tamarind are many and it is used extensively in the Indian system of medicine, Ayurveda. Tamarind preparations are universally recognized as refrigerants in fevers and as laxatives and carminatives. Alone, or in combination with lime juice, honey, milk, dates, spices or camphor, the pulp is considered effective as a digestive, even for elephants, and as a remedy for biliousness and bile disorders, and as an antiscorbutic. In native practice, the pulp is applied on inflammations, is used in a gargle for sore throat and, mixed with salt, as a liniment for rheumatism. It is, further, administered to alleviate sunstroke, Datura poisoning, and alcoholic intoxication.
Tamarind leaves and flowers, dried or boiled, are used as poultices for swollen joints, sprains and boils. Lotions and extracts made from them are used in treating conjunctivitis, as antiseptics, as vermifuges, treatments for dysentery, jaundice, erysipelas and hemorrhoids and various other ailments. The fruit shells are burned and reduced to an alkaline ash which enters into medicinal formulas. The bark of the tree is regarded as an effective astringent, tonic and febrifuge. Fried with salt and pulverized to an ash, it is given as a remedy for indigestion and colic. A decoction is used in cases of gingivitis and asthma and eye inflammations; and lotions and poultices made from the bark are applied on open sores and caterpillar rashes. The powdered seeds are made into a paste for drawing boils and, with or without cumin seeds and palm sugar, are prescribed for chronic diarrhea and dysentery. The seedcoat, too, is astringent, and it, also, is specified for the latter disorders. An infusion of the roots is believed to have curative value in chest complaints and is an ingredient in prescriptions for leprosy.