[Amchoor, Green Mango; Mangifera indica]
In India some mangos are picked green (unripe), cut, dried and sold as chunks or in powdered form (Amchur powder). This is a very important souring agent in the drier and more northern areas of India where lemons and limes are expensive and quickly rot. As a powder it is light weight and lasts a long time, similar to the Sumac used in the Levant and Near East.
Amchur is a very convenient ingredient in dry Masalas (spice mixes) and widely used in that way. It is also used in stir fries, curries, chutneys, pickles, fruit salads, and pastry fillings, anywhere a sour and somewhat fruity flavor is desired. It is also used in marinades for meats as it provides tenderizing enzymes.
More on Cashew / Mango Family.
This is the form in which Amchoor is most commonly available, and most
easily used. It is available in any Indian market and in many multi-ethnic
markets here in North America.