Processing of Turmeric:-

• Processing of turmeric includes curing, polishing and coloring.

Curing

• The fresh rhizomes are boiled In lime water or sodium bicarbonate containing 20 g each of sodium bisulphate and hydrochloric acid per 45.3 kg of rhizomes.
• The boiled rhizomes are then dried in the sun by spreading in 5 – 7 cm thick uniform layers for 10 – 15 days till they become hard and bristle to produce the metallic sound when break.
• The yield of cured turmeric generally ranges from 20 – 30 percent of fresh turmeric.

Polishing

• The dried fingers are rubbed manually or by drum to get the smooth finish material.
• The drum may be hand or power operated.
• The drum is filled with the cured turmeric and rotates to 30 – 40 rpm.
• The rhizomes are polished by mutual rubbing and abrasion of the surface against the mesh.
• The polished turmeric yields 15 – 25% of the raw material.

Colouring

• Coloring facilitates good appearance and better finish of the product which results in the better price of the produce in the market.
• The coating emulsion is prepared by using alum 0.04 Kg, turmeric powder 2 Kg, castor oil 0.4 Kg, sodium bisulphate 30 g and concentrated hydrochloric acid 30 ml.
• This is sufficient for 100 Kg of half polished turmeric.
• After coating of fingers with the emulsion they are dried in the sun.