It is true that once an apple is peeled, it takes very little time before it turns light brown, then completely brown, making it noticeably less appetizing.
It is due simply to the oxidation of the apple's flesh, combined with a chemical reaction between its different components.
This chemical reaction is caused by the contact between an enzyme, polyphenol oxidase, and carbolic acid contained in the cells of the fruit.
Question submitted by: Wonder-Why.com
Answer submitted by: Wonder-Why.com