Turmeric spice Haldi, Huldi) comes from a plant of the ginger family and, like ginger, the part of the plant that is used is the rhizome (the underground part of the stem). The rhizomes are boiled for several hours, dried and then ground into powder.
In food it has an earthy, slightly hot and slightly bitter taste, and a mustard like smell. It is not the most standard ingredient in curry powders but is often found there.
It is a native of South East Asia and its use can be dated back nearly 4000 years. It has been used as an important spice, for beauty products, in religious ceremonies and also as a dye (see those Buddhist monks' yellow robes - that's turmeric that is).
The most noticeable effect when using turmeric spice in cooking, is that it turns everything bright yellow (the active ingredient, curcumin, is registered as a food additive, E100); it is used in English Mustard and Piccalilli to give them their bright yellow colour, as well as numerous other things like popcorn, biscuits and cakes.
It is quite often added to starchy foods like potatoes, both to add colour and because of its digestive qualities; it is used in pilau rice so give the yellow colour and improve the flavour.
Although it can be bought whole, I have never seen it in this country - you can probably get it online. The powder will lose its flavour over time so buy sensible quantities and keep in a cool dark place. Interestingly, it will retain its ability to turn everything yellow almost indefinitely.
Nutritionally turmeric spice contains a good dose of Vitamins C and B6 with a smattering of other Vitamins. It also contains fairly spectacular quantities of Manganese as well as Iron and Magnesium.
Medicinally turmeric has antiseptic and antibiotic properties, (you may see chefs rubbing it on small cuts and burns). In India and Pakistan it is recommended for gastric discomfort and is reckoned to purify the blood. It is also a good digestive.
Curcumin is being investigated in relation to treatment of a number of cancers and it has been shown that curcumin can kill certain kinds of cancer cells under laboratory conditions.
Or Search the Site to find something