Polyphenol oxidase (PPO) in bruised apples, potatoes, bananas catalyses phenol + O₂ → o-quinone, which polymerises into melanin-like pigments. Inhibited by low pH (citric acid), reducing agents (ascorbic acid), or blanching.
Polyphenol oxidase (PPO) in bruised apples, potatoes, bananas catalyses phenol + O₂ → o-quinone, which polymerises into melanin-like pigments. Inhibited by low pH (citric acid), reducing agents (ascorbic acid), or blanching.