Indian curries change character every few hundred kilometres. We distinguish them not by their main ingredients but by the souring agents.
Malabar tamarind or kudam puli is a souring agent used in a number of curries in Kerala and Karnataka. Also known as Garcinia Gambogia, it may help in weight loss.
Coconut vinegar is used in a number of dishes of Goan cuisine as a souring agent and a flavour -enhancer. It's also used in preparing the desi Goan alcoholic drink - coconut feni.