Citric Acid is a weak organic tricarboxylic acid that naturally occurs in fruits with the chemical formula C6H8O7. Besides occurring naturally in fruits citric acid can also be created through industrial means. The major industrial means to get citric acid is by feeding cultures of A. niger sucrose or glucose-containing medium to produce citric acid. After the mold is filtered out of the resulting solution, citric acid is isolated by precipitating it with calcium hydroxide to yield calcium citrate salt, from which citric acid is regenerated by treatment with sulfuric acid, as in the direct extraction from citrus fruit juice.
Citric acid is used as a flavoring and preservative in food and beverages, cleaning and chelating agent, and as an acidulant in cosmetic goods. Besides these applications it can also be used as adhesives and sealant chemicals, agricultural chemicals, bleaching agents, corrosion inhibitors and anti-scaling agents, finishing agents, intermediates, laboratory chemicals, lubricants and lubricant additives, oxidizing/reducing agents, plating agents, surface treating agents, process regulators, processing aids, propellants, blowing agents, solids separation agents, surface active agents, and viscosity adjustors.