Colourless, crystalline organic compound (C 6 H 8 O 7 ), one of the carboxylic acid s.
It is present in almost all plants (especially citrus fruits) and in many animal tissues and fluids. It is one of a series of compounds involved in the physiological oxidation (see oxidation-reduction ) of fat s, protein s, and carbohydrate s to carbon dioxide and water (see tricarboxylic acid cycle ). It has a characteristic sharply sour taste and is used in many foods, confections, and soft drinks. It is added to certain foods to improve their stability in metal containers. Industrially, it is used as a water conditioner, cleaning and polishing agent, and chemical intermediate.