Question

Why a sliced apple on exposure to air turns brown after sometimes

Answer 1

Hiiii Dear

When an apple is injured (or cut into pieces), the plant tissue is exposed to oxygen. This triggers an enzyme known as polyphenol oxidase (PPO) to—wait for it—oxidize polyphenols in the apple's flesh. ... Enzymatic browning is not unique to apples. Pears, bananas, and eggplants also turn brown fairly quickly when cut.