How do you know an apple is rotten if it doesn’t turn brown?

When an apple is cut, bruised, or exposed to air, it undergoes a natural process called enzymatic browning, which causes it to turn brown. Apples contain an enzyme called polyphenol oxidase (PPO), which is normally stored in separate compartments within the apple’s cells. When the apple’s cells are damaged, such as through cutting or bruising, these compartments break open, allowing PPO to come into contact with polyphenols and oxygen in the air. Polyphenols are naturally occurring compounds found in apples. When PPO comes into contact with polyphenols, a chemical reaction occurs, resulting in the formation of brown pigments known as melanins. These melanins are responsible for the brown discoloration seen on the apple’s surface. <a href="https://medium.com/@chichinyung/how-do-you-know-an-apple-is-rotten-if-it-doesnt-turn-brown-2d7c0fba5249">Click Here</a>