citric acid

a white, crystalline, water-soluble powder, C₆H₈O₇·H₂O, a tribasic acid having a strong acidic taste, an intermediate in the metabolism of carbohydrates occurring in many fruits, esp. limes and lemons, obtained chiefly by fermentation of crude sugar or corn sugar: used chiefly in the flavoring of beverages, confections, and pharmaceuticals.

[1805-15]

* * *

Colourless, crystalline organic compound (C₆H₈O₇), one of the carboxylic acids.

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 fats, proteins, and carbohydrates 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.

* * *

▪ chemical compound

      a colourless, crystalline organic compound belonging to the family of carboxylic acids, present in practically all plants and in many animal tissues and fluids. It is one of a series of compounds involved in the physiological oxidation of fats, proteins, and carbohydrates to carbon dioxide and water (see tricarboxylic acid cycle).

      First isolated from lemon juice by a Swedish chemist, Carl Wilhelm Scheele (Scheele, Carl Wilhelm), in 1784, citric acid is manufactured by fermentation of cane sugar or molasses in the presence of a fungus, Aspergillus niger. It is used in confections and soft drinks (as a flavouring agent), in metal-cleaning compositions, and in improving the stability of foods and other organic substances (by suppressing the deleterious action of dissolved metal salts).

* * *