Citric acid is a weak, white, water-soluble organic carboxylic acid that occurs naturally in many fruits and vegetables, especially citrus fruits. Of all the acids, citric acid is the only edible acid. In biochemistry, it is known as an intermediate in the citric acid cycle, which occurs in the metabolism of all aerobic organisms. More than one million tons of citric acid is produced every year.
Citric acid can exist in both anhydrous and aqueous forms. The anhydrous form is obtained by crystallization of citric acid in hot water. Aqueous form of this acid is created by crystallization in cold water. An aqueous form is converted to an anhydrous form by heating. Citrate is a derivative of citric acid and forms citrate salt with many metals, the most important of which is calcium citrate (lemon essence), which is used to preserve food from spoilage and make it tasty. Citric acid is widely used in the food industry as a flavoring agent.
Citric acid in the production of photographic film, soap and detergents, creams, health gels, food industry (acidity regulator and flavoring in drinks), pharmaceuticals, paint industries, oil extraction and metalworking, cosmetics, in Shampoo is used to clean hair and in the formulation of hair color, etc. Also, citric acid can be used as a blood acidity regulator.
