Introduction: Turmeric is an underground rhizome which is used as condiment, dye stuff, drug, cosmetic & traditional item of export. India is the largest producer of turmeric. In India, Telangana is the largest producer accounting 31% of total country’s production.
Processing of Turmeric
Fresh rhizomes are not useful for marketing. Curing makes fresh rhizomes marketable. Curing involves boiling, drying & polishing.
A. Boiling:It can be done either by traditional or modern method.
1. Traditional Method: water is poured to cover rhizomes in the vessels of copper or galvanized iron or earthen material. Mother rhizomes and fingers should be boiled separately, since fingers take long time for boiling. Stop boiling when froth, fumes with typical odor comes.
Rhizomes yield to finger pressure. Over cooking should be avoided as it spoils the color, while under cooking renders the dried product brittle.
2. Improved Method: 50kg of cleaned rhizomes are taken in a perforated trough made of GI sheet. It is immersed in a pan. Alkaline solution (0.1% sodium carbonate/ sodium bicarbonate) is poured in the trough. Boil till fingers become soft. Alkaline solution helps in imparting orange yellow color to the core.
B. Drying:The boiled rhizomes are sun dried in 5.7cm thick layers for 10-15cm layers. Rack frequently for uniform drying. Dry until they become hard, brittle, break with a metallic sound. After drying they should possess only 8-10% moisture.
C. Polishing: The dried rhizomes are smothered by manual or mechanical rubbing. Manually they rubbed on hard surface or trampled under feet. Mechanically they are polished by mechanically operated polishing drums.
D. Coloring: They are colored to improve the appearance. Half polished fingers are colored. Rhizomes are colored in two ways. They are
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Dry coloring- Turmeric powder is added in the last 10 min to polishing drum.
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Wet coloring- turmeric powder is suspended in water & mixed by sprinkling.
For Brighter color- Boiled, dried, half polished fingers are taken in baskets and shaken continuously with an emulsion of
a. 2 kg Turmeric powder
b. 0.04 kg Alum
c. 0.14 kg Castor seed oil
d. 30 g Sodium Bisulphate &
e. 30 ml HCL
Colored rhizomes are again sun dried before sending to market.
