Curcuma longa L. Syn. Curcuma domestica Valet.
Description: Turmeric (Curcuma longa) is native to Asia and India. The tuberous rhizomes or underground stems of turmeric are used from antiquity as condiments, a dye and as an aromatic stimulant in several medicines. Turmeric is a very important spice in India, which produces nearly the whole world's crop and uses 80% of it. Presently, it is cultivated in China, Taiwan, Indonesia, Sri Lanka, Australia, Africa, Peru and the West Indies. Turmeric usage dates back nearly 4000 years, to the Vedic culture in India, when turmeric was the principal spice and also of religious significance. It is much revered by Hindus and associated with fertility. In today's India, turmeric is still added to nearly every dish, be it meat or vegetables. Turmeric has been used in Indian systems of medicine for a long time.
It is listed in an Assyrian herbal dating from about 600 BC and is also mentioned by Dioscorides. In Malaysia, a paste of turmeric is spread on the mother?s abdomen and on the umbilical cord after childbirth, not only to warn off evil spirits, but also for its medicinal value. Both the East and the West have held its medicinal properties in high regard. Rhizomes are the used plant part. Fresh turmeric leaves are used in some regions of Indonesia as a flavouring. In fresh state, the rootstock has a aromatic and spicy fragrance, which by drying gives way to a more medicinal aroma. On storing, the smell rather quickly changes to earthy and unpleasant. Similarly, the colour of ground turmeric tends to fade if the spice is stored too long. It is called ?Indian saffron? because of its orange ? yellow colour. In some languages, the names of turmeric just mean "yellow root"; English turmeric derives from the (now obsolete) French terre-m?te (Latin terra merita, "meritorious earth"), probably because ground turmeric resembles mineral pigments (ocher). The genus name Curcuma is of the same origin, being a Latinization of Arabic kurkum meaning saffron.
Distribution: Turmeric is not known in a truly wild state. Turmeric (Curcuma longa) is native to Asia and India. It was domesticated in Southern or South East Asia. The wild Curcuma sp., from which C. longa evolved, is presumed to have attracted attention as an incidental source of food, or because of its yellowish colour it might have acquired magical properties. Turmeric usage dates back nearly 4000 years, to the Vedic culture in India, when turmeric was the principal spice and also of religious significance. In biblical times, it was used as a perfume as well as a spice. Turmeric has been used in Indian systems of medicine for a long time. It is listed in an Assyrian herbal dating from about 600 BC and is also mentioned by Dioscorides. Turmeric is distributed in sites other than India, especially in Celebes, the Moluccas and Polynesia. This suggests an early cultural connection between the people of these areas and the indigenous pre Aryan cultivators of India. It reached China before the 7th century A.D., East Africa in 8th century and West Africa in the 13th century. It was introduced into Jamaica by Edwards in 1783.
Botany: Turmeric is a herbaceous perennial with a rhizome from which arises tufts of large, broad, lanceolate, bright green leaves acute at both ends. The plant grows up to 60 to 90 cm high. Leafy shoots are erect, bearing 6-10 leaves with the leaf sheath forming a pseudostem. The ligule is a small lobe (1mm long). The sheath near the ligule has ciliate margins. The inflorescence is a cylindrical spike, 10-55 cm long, 5-7 cm wide and terminal on the leafy shoot. The flowers are yellow or pale yellow, borne in a spike. They arise from two buds situated in the axils of bracts and mature successively. Bracts are greenish-white; the uppermost tinged with pink. The bracteoles are thin and elliptic. The calyx is short, unequally toothed and split nearly half way down on one side. The corolla is tubular at the base and the upper half s cup-shaped. There are two lateral staminodes. The lip or labellum is obovate. The ovary is inferior and trilocular with a slender style held by anther lobes and passing between them. Fruits are seldom. The primary tuber at the base of the aerial stem is ellipsoidal bearing many rhizomes; straight or little curved, with secondary branches in two rows and further tertiary branches, the whole forming a dense clump. Rhizomes have a distinctive taste and smell, brownish and scaly outside and the inside is bright orange in colour. The roots are fleshy, often ending in a swollen starchy tuber.
Cultivation: Turmeric cultivation is confined to South East Asian countries such as India, Sri Lanka, China and Indonesia. The main turmeric growing states in India are Andhra Pradesh, Maharashtra, Orissa, Tamilnadu, Karnataka and Kerala. Turmeric requires a hot and moist climate. It thrives the best on loamy or alluvial, loose, friable and fertile soils. It grows at all places ranging from sea level to an altitude of 1220m above MSL. It is very sensitive to low atmospheric temperature. It is grown both under rainfed and irrigated conditions. Like other tuber crops, turmeric also requires deep tilth and heavy manuring for high yields. Beds of convenient length and width are prepared based on the topography of the land. Planting is done either on raised beds or on ridges during May -June.
Turmeric is propagated vegetatively through rhizomes. Healthy and disease-free rhizomes with one or two sprouting buds are used generally for planting at a spacing of 30 x 25 cm on beds and at 45 cm apart in the case of ridges and furrows. A thick mulching with green leaves is given immediately after planting. In raised beds, the seeds begin to sprout in about a month after planting while the sprouting takes place in 15 days when irrigated. Regular weeding and plant protection measures should be undertaken. Common insect pests of turmeric are shoot borer (Conogethes punctiferalis), rhizome scale (Aspidiella hourtii) and leaf roller (Udaspes folus). Among the nematode pests, root knot nematodes (Meloidogyne spp.) burrowing nematodes (Radopholus similis) and lesion nematodes (Pratylenchus spp.) are prominent. Rhizome rot caused by Pythium sp., leaf spot due to Colletotrichum capsici and leaf blotch by Taphrina maculans are the major fungal diseases of turmeric.
The crop becomes ready for harvest in about 8-9 months after planting. The main harvest season begins from February and extends up to April. Turmeric is harvested when leaves turn yellow and start drying up. In harvesting, the whole clump is lifted out with the dry plant, then the leafy tops are cut off, the roots are removed, all the adhering mud particles are shaken or rubbed off and the rhizomes are then washed well with water. The fingers, sometimes called the daughter rhizomes, are separated from the mother rhizomes and kept in shade for 2-3 days.
Aroma and flavor: Raw turmeric rhizomes have to be cured for both colour and aroma. For this, the fingers and bulbs are boiled separately in water for 30 to 45 minutes until the rhizomes are soft. This procedure gets rid of the ?raw? colour, reduces drying time, gelatinises the starch and gives the turmeric a more uniform colour. Water is then drained and the turmeric sun dried for 10-15 days until they become dry and hard. For imparting orange yellow colour, the rhizomes are boiled in lime water or sodium bicarbonate solution. The dried produce is cleaned and polished mechanically in a drum rotated by hand or by power.
Turmeric oleoresin is obtained by solvent extraction of the ground spice. It is orange-red in colour and consists of colouring matter, volatile oil, fatty oils and bitter principles. The volatile oil gives the turmeric its characteristic flavour. The important quality attributes of turmeric are size, physical form, colour, curcumin content, maturity, weight or bulk density, length and thickness, intensity of colour of the core and aroma.
Turmeric contains two primary constituents, the colouring matter and the volatile oil. The volatile oil of turmeric is about 1.5 -6.0% and is composed of a variety of sesquiterpenes, many of which are specific for the species. Several sesquiterpenes, germacrone, turmerone, ar-(+)-, a-, b-turmerones; ?bisabolene; a-curcumene; zingiberene; ?sesquiphellandene, bisacurone; curcumenone; dehydrocurdione; procurcumadiol; bis-acumol; curcumenol; isoprocurcumenol epiprocurcumenol; procurcumenol; zedoaronediol; curlone; and turmeronol A and turmeronol B, have been recorded from the rhizomes. Most important for the aroma are turmerone (max. 30%), ar-turmerone (25%) and zingiberene (25%). A ketone, and an alcohol identified as p-tolylmethyl carbinol, have been obtained. Conjugated di-arylheptanoids (1,7-diaryl-hepta-1,6-diene-3,5-diones, e.g. curcumin) are responsible for the orange colour and probably also for the pungent taste (3 to 4%). The crystalline coloring matter, curcumin, is a diferuloyl methane. It dissolves in concentrated sulphuric acid giving a yellow-red coloration.
The rhizomes contain curcuminoids, curcumin , demethoxy curcumin, bis- demethoxycurcumin, 5'- methoxycurcumin and dihydrocurcumin which are found to be natural anti-oxidants. A new curcuminoid, cyclocurcumin, was isolated from the nematocidally active fraction of turmeric. The fresh rhizomes also contain two new natural phenolics which possess antioxidant and anti-inflammatory activities and also two new pigments. The rhizomes are also reported to contain four new polysaccharides-ukonans - having activity on the reticuloendothelial system, along with stigmasterol, ?sitosterol, cholesterol and 2-hydroxymethyl anthraquinone.
Culinary use: Turmeric is a very unique and versatile natural plant product combining the properties of (a) a spice or flavourant, (b) a colourant of brilliant yellow dye, (3) a cosmetic and (4) a drug. It is mainly a spice that the colouring properties are usually more important than its flavour attributes. Turmeric is the major ingredient in curries and curry powders, contributing flavour as well as the characteristic yellow colour. It is also used in chutneys and pickles. In South East Asia, the fresh spice is much preferred to the dried. In Thailand, the fresh rhizome is grated and added to curry dishes; it is also part of the yellow curry paste. Yellow rice (nasi kuning) is popular on the Eastern islands of Indonesia; it derives its colour from fresh or dried turmeric. In Bali, where alone in Indonesia hinduism has survived, a tasty nasi kuning is prepared from rice, turmeric, coconut milk and aromatic leaves. It is considered a "cultic dish" and sacrificed to the Gods. Moreover, Indonesian cooks frequently add dried turmeric to their stews and curries. Western cuisine does not use turmeric directly, but it forms part of several spice mixtures and sauces; it is also used in the food industry as an edible colouring in mustards, butter, cheese and liqueurs. Turmeric is used for dyeing wool and cotton fabrics. It is also employed as a colouring material in pharmacy, confectionery, food industries and also in paints and varnishes.
Medicinal use: Traditionally turmeric is being used in Indian System of medicine. It has several medicinal properties like stomachic, carnivative, tonic, blood purifier, vermicide and antiseptic. The active constituent of turmeric, curcumin, has been shown to have a wide range of therapeutic effects. Because it is a strong antioxidant, it protects against free radical damage. Curcumin has also been shown to have a marked anti-inflammatory effect. It accomplishes this by reducing histamine levels and possibly by increasing production of natural cortisone by the adrenal glands. Curcumin also protects the liver from a number of toxic compounds. It has also been shown to reduce platelets from clumping together, which improves circulation and helps protect against atherosclerosis. There are numerous studies showing cancer-preventing effect of curcumin; which may be due to its powerful antioxidant activity in the body. Anticancer properties of turmeric are recently reported.
Other use: In cosmetics also turmeric has a major role. It is an inexpensive and indigeneous beauty aid. Considerable quantities of turmeric are converted as ?kumkum? used for tilak by Indians. Smearing with turmeric paste cleans skin and beautifies it. Its antiseptic and healing properties prevent and cure pimples.