Food Chemistry
Polyphenol oxidase PPO
A copper-containing enzyme responsible for enzymatic browning in cut fruit and vegetables. Optimum pH is around 6–7 and it is largely inactivated above about 80 °C.
The enzyme responsible for cut apples, bananas and potatoes turning brown — the same reaction as enzymatic browning, named for the enzyme that drives it.
Related terms
Enzymatic browning
Food ChemistryBrowning catalysed by polyphenol oxidase, which oxidises phenolic compounds to quinones that polymerise into brown melanins. It requires oxygen, the enzyme, and a phenolic substrate.
Blanching
Processing & PreservationA short heat treatment, usually 70–100 °C, applied before freezing, drying or canning, primarily to inactivate enzymes.
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