Souring agent
An ingredient added to a dish to give it sourness.
Also: sour agent, acidulant
Sourness balances salt, fat, sweetness and heat, and every cuisine has its preferred sources. Vinegar and lemon are common in Europe. Lime is used in Mexico and Southeast Asia. Tamarind is used across South and Southeast Asia and in parts of Africa. Indian cooks also use kokum, dried green mango powder called amchur, raw mango, tomatoes and curd. The Middle East has sumac, pomegranate molasses and dried limes. Fermented foods bring sourness of their own.