Citric acid is a natural compound, present in all animal and vegetable material. Citric acid is the most widely used acid and pH control agent in the food industry. It strengthens the work of Antioxidants such as Ascorbic Acid (vitamin C, E300), and prevents fruits from turning brownish; it is also used as an acidulant in the production of beer and jam. Citric acid stabilises sweets and confectionery, to prevent crystallisation of sugar.
Citric acid is present in large quantities in fruits, especially citrus fruits, in which it is predominant. In view of the fact that the isolation of citric acid from fruits is very expensive, it is commercially produced from sugar with the help of bacteria and yeasts.