Botanical name: Curcuma longa
Turmeric is a widely used spice and medicinal product obtained from the rhizomes of Curcuma longa. It has been used in Asia for thousands of years and is intimately associated with the social and cultural lives of Indians. Turmeric is a component in many Ayurvedic, Siddha, Unani, and traditional Chinese medicines. It is extensively used without fail in Indian kitchens. It is mostly consumed in powdered and pulverized forms. However, fresh rhizomes can also be used. The calorific value of dry turmeric is 349 kilocalories, respectively. The characteristic aroma and flavour in turmeric are due to the presence of turmerone, zingeberene, and 1,8-cineole.
India is the largest producer and exporter of turmeric in the world. It is estimated that about 70-80% of the world's production of turmeric is contributed by India alone. Other major producers of turmeric are Bangladesh, Pakistan, Sri Lanka, Taiwan, China, Myanmar, and Indonesia. In India, major turmeric-growing states are Andhra Pradesh (283,541 Tonnes /56,822 ha; 58.5% of production), Tamil Nadu (64,536 Tonnes), Odisha, West Bengal, Assam, Maharashtra, and Karnataka.
ORIGIN AND DOMESTICATION
Turmeric is native
to the Indian subcontinent and Southeast Asia. It has been used and
domesticated in Asia for thousands of years. The
various evidences suggest that Indians have been using turmeric for the last
more than 4,000 years. Presently, turmeric is cultivated in Southeast Asia, Oceania,
and some countries of western Africa.
MORPHOLOGY
Turmeric is an herbaceous plant, surviving
through perennial rhizomes. Many fibrous adventitious roots arise from the
rhizomes (underground stem). A rhizome is highly branched, yellow to orange in
colour, cylindrical, and aromatic. Pseudostems are 12-20 cm in height. Many
leaves arise from the rhizomes. The leaves are distichous (arranged alternately in two rows) and long-petioled.
They are
divided into leaf sheath, petiole, and lamina or leaf blade. The leaf sheaths
form the false stems. The lamina of each
leaf is oblong
to elliptic and about 60-115 cm in length and 25-45 cm
in breadth. Lamina has a prominent midrib. The inflorescence, a spike, arises
directly from the rhizome during the rainy season. It measures about 10-18 cm in length. The flowers are pale-yellow, covered by pinkish
bracts, bisexual
and zygomorphic. Three sepals are white, fused, and with unequal calyx teeth.
Three petals are bright-yellow and fused to form a corolla tube up to 3 cm
long. Out of six stamens, only the median stamen of the inner circle is fertile
(5 are converted into staminodes). Carpels are three and fused. Turmeric does not bear fruits, as it is a
sterile triploid. However, if it bears fruit rarely, it is a capsule.
CULTIVATION
Turmeric can be grown in diverse agro-climatic
conditions prevailing in India. However, a temperature range of 20-35°C, annual rainfall of more than 150 cm and altitude of less than 1500 m are best suited to the crop. It
thrives best in well-drained sandy or clay loam soils with enough organic
matter and a pH range of 4.5-7.5. The land is well prepared
during early monsoon showers and brought to a fine tilth by giving three-four
ploughings. Well-decomposed farmyard manure or
compost @ 30-40 Tonnes/ha is applied during the ploughings or as a basal
dressing by spreading over the beds. Biofertilizer (Azospirillum) can also be used in turmeric crops. Beds
of 1.0 m in width, 30 cm in height, and of convenient length
are prepared with a spacing of 50 cm between the
beds. Planting is done by forming ridges and furrows. The whole or split mother
and finger rhizomes are used for planting material. They are planted at a distance of 20-30 cm from each other either during
the pre-monsoons or at the onset of monsoons. A seed rate of 2,500 kg of rhizomes is needed
for one hectare of land. Turmeric
crop becomes ready for harvesting in seven to nine months depending upon the
variety and time of sowing. The leaves turn light brown to yellowish in colour
and become dry at maturity.
The land is ploughed, and the rhizomatous clumps
are carefully lifted with a spade in case of manual harvesting. However,
harvesting can also be done through tractors. The harvested rhizomes are
collected and cleared of all the extraneous matter.
VARIETIES
1.Traditional Cultivars: Duggirala, Tekkurpet, Sugandham,
Amalapuram, Erode local, Salem, Alleppey, Moovattupuzha, and Lakdong.
2.Improved Cultivars: IISR
–Pragati, IISR-Kedaram, Prathibha, Prabha, Suguna, Sudharsana, Suvarna,
IISR-Alleppey Supreme
CHEMICAL CONSTITUENTS
The general
chemical constituents in turmeric powder are
60–70% carbohydrates, 6–13% water, 6–8% protein, 5–10% fat, 3–7% minerals, 3–7%
essential oils, 2–7% fiber and 1–6% curcuminoids. The rhizomes contain curcuminoids (1–6%) which are responsible for the yellow colour. Curcumins
(diferuloylmethane) comprise curcumin I (curcumin),
curcumin II (demethoxycurcumin) and curcumin III
(bisdemethoxycurcumin).
Essential
oils such as turmerone, germacrone, atlantone, and zingiberene form the major fraction
of volatile oils.
Other Species of Curcuma
1.Zedoary: Curcuma zedoaria
2.Yellow Zedoary or Wild Turmeric: Curcuma
aromatica
3.Mango Ginger: Curcuma amada
USES
1. As
a Spice: Indians have been using turmeric
as a spice for thousands of years. It is used as an
additive to improve the palatability of foods. It also helps in the storage and
preservation of food articles.
2. Medicinal
Uses: Turmeric has
magical medicinal properties. It is extensively used
in Ayurvedic, Unani, Chinese, and traditional medicinal preparations. Turmeric
rhizomes are used as a household remedy in India and Nepal. Some
of the medicinal uses are:
- Curcumins have strong antioxidant property.
- Turmeric powder has wound-healing properties and is also used in the treatment of skin diseases.
- Turmeric is reported to be a stomachic, tonic, blood purifier, anti-inflammatory, and liver protectant.
- It has been found effective against biliary disorders, cough, anorexia, diabetic wounds, rheumatism, and sinusitis.
- Recent epidemiological observations have suggested that turmeric consumption may reduce certain forms of cancers.
3. Food Colourant: Turmeric can be
used as a food colourant (for butter, cheese, etc.) in place of the synthetic dye
tartrazine. It is one of the principal ingredients in curry powder.
4. Pickles: Turmeric powder is
added to pickles as flavouring and colouring agent.
5. Dye: Turmeric powder
was used for dying cotton, silk, and wool in old
times.
6. Sacred Uses: Turmeric is
considered sacred by Hindus. It is offered to deities during religious
ceremonies. Turmeric vermilion is put on the forehead in some temples and
during sacred occasions.
Turmeric is used as one of the nine plants of navapatrika during the Durga festival. The Haldi ceremony is performed during Hindu and Muslim wedding ceremonies in India
and neighboring countries.
7. Sweet Dishes: Turmeric is also used
in some sweet dishes in India. Haldi ke
Laddu are quite famous during winter.
8. Value-Added Products: Sweet candies can be prepared of turmeric
rhizomes with sugar syrup.
9. pH Indicator: A paper is steeped in a tincture of turmeric and allowed to dry. This paper can be used as an indicator of acidity and alkalinity. When this paper is dipped in acidic to neutral solutions, it turns yellow. When dipped in alkaline solution, it turns brown to reddish-brown.