Why does olive oil turn apples brown?

Olive oil itself doesn't directly cause Apples to turn brown; rather, it's the exposure of Apple flesh to air that triggers oxidation. When Apples are cut or bruised, their cells are damaged, releasing enzymes like polyphenol oxidase, which react with oxygen and phenolic compounds in the Apple, leading to browning. Although olive oil can coat the surface and slow down this oxidation process by limiting air exposure, it doesn't prevent browning entirely.