What is Polyphenol oxidase in an apple?

Polyphenol oxidase (PPO) is an enzyme found in Apples that plays a key role in the browning process of the fruit when it is cut or damaged. It catalyzes the oxidation of phenolic compounds to form brown pigments known as melanins, which can affect the aesthetic quality and flavor of the Apple. This enzymatic reaction is a defense mechanism against pests and pathogens, but it can also lead to undesirable changes in appearance and taste. Reducing PPO activity can help maintain the freshness and visual appeal of cut Apples.