Citric acid

Citric acid is a weak organic tribasic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in the metabolism of all aerobic organisms.

More than a million tons of citric acid are manufactured every year. It is used widely as an acidifier, as a flavoring, and as a chelating agent.^[8]

A citrate is a derivative of citric acid; that is, the salts, esters, and the polyatomic anion found in solution. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate. When part of a salt, the formula of the citrate ion is written as C₆H₅O₇³⁻ or C₃H₅O(COO)₃³⁻.

Contents

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• 1Natural occurrence and industrial production
• 2Chemical characteristics
• 3Biochemistry
  • 3.1Citric acid cycle
  • 3.2Other biological roles
• 4Applications
  • 4.1Food and drink
  • 4.2Cleaning and chelating agent
  • 4.3Cosmetics, pharmaceuticals, Dietary Supplements, and Foods
  • 4.4Other uses
• 5Synthesize solid materials from small molecules
• 6Safety
• 7Compendial status
• 8See also
• 9References