Citric acid is a weak organic acid found naturally in citrus fruits. It is a tricarboxylic acid with three carboxylic acid groups and one hydroxyl group, playing a central role in the Krebs cycle (citric acid cycle) in cellular metabolism. It appears as a white crystalline powder with a sour taste and is widely used as a food additive for flavoring and preservation, as well as in pharmaceuticals, cosmetics, and cleaning products. It acts as a chelating agent and pH regulator. In food applications, it enhances flavor and prevents oxidation. Chemically, it is highly soluble in water and forms salts with metals. Its structure allows it to participate in esterification and other reactions.