Melanins are high-molecular-weight pigments with reddish-brown to black colour, formed by the action of oxidases on phenols — the chemistry behind enzymic browning. Widely distributed in animals and plants, they arise when polyphenol oxidases (catechol oxidases, EC 1.10.3.1, also called diphenol oxidases, phenolases or tyrosinases) oxidise phenols to quinones, which polymerise into dark pigments. In foods, melanin formation darkens cut fruits, vegetables, mushrooms and crustaceans, and is managed with blanching, acidification, ascorbic acid or sulphites, modified-atmosphere packaging and cold storage to limit enzyme activity and oxygen exposure.