BOTANICAL NAME: Curcuma longa
PROCESS: Sun dried rhizome of turmeric are powdered for CO2 extraction
PLANT PART: Rhizome
HARVEST SEASON: The crop normally gets ready for harvest in about 7 to 10 months depending upon the varieties. When fully mature the leaves turn yellow and pseudo stems begin to dry. Harvested turmeric rhizomes are cleaned off mud and other extraneous materials adhering to them and subjected to curing within 2-3 days after harvest so as to ensure the quality of the end product.
Fingers and mother rhizomes will have to be boiled separately. The whole mass is boiled till the rhizomes become soft. The correct stage of cooking can be judged by piercing a wooden needle through the rhizome. If the rhizomes are properly cooked, the needle will pass through the rhizome without resistance. The cooked rhizomes are taken out of the pan by lifting the trough and draining the solution into the pan. The fingers are then dried in the sun by spreading them as a thin layer on bamboo mats or drying floor. Artificial drying at a maximum temperature of 65ºC gives a bright coloured product than that of sun drying especially for sliced turmeric. In order to smoothen the rough and hard outer surface of the boiled dried turmeric and also to improve its colour, it is subjected to polishing. There are two types of polishing, hand polishing and machine polishing.
MAJOR CONSTITUENT: curcuminoids, such as curcumin, demethoxycurcumin, and bisdemethoxycurcumin, turmerone