Kojic acid is an organic compound with the formula HOCH2C5H2O2OH. It is a derivative of 4-pyrone that functions in nature as a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji.[2][3][4] Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine.[2] It is a mild inhibitor of the formation of pigment in plant and animal tissues, and is used in food and cosmetics to preserve or change colors of substances.[5] It forms a bright red complex with ferric ions.[6]
^Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.
^ abBentley, R. (2006). "From miso, sake and shoyu to cosmetics: a century of science for kojic acid". Nat. Prod. Rep. 23 (6): 1046–1062. doi:10.1039/b603758p. PMID17119644.