Polyphenol oxidases

Enzymes also known as catechol oxidases, that oxidize phenolic compounds and drive the enzymatic browning that darkens cut apples, potatoes, mushrooms, and shrimp. Processors control them with blanching, acidification, sulfites where permitted, or ascorbic acid to protect appearance and flavor in fresh-cut and frozen products. The same enzymes are harnessed deliberately in tea and cocoa fermentation, where controlled oxidation builds the desired color, aroma, and taste. Because browning is among the first quality defects consumers notice, managing polyphenol oxidase activity is a daily task in fruit and vegetable processing.