A lesser fruit would have given up at this point, succumbing to rot. But not you, because your arsenal of defensive weapons isn’t limited to your armor-like peel, you also have access to chemical and biological weapons. One such weapon is a protein called catechol oxidase. - See more at: http://www.quickanddirtytips.com/education/science/why-do-apples-turn-brown#sthash.prYTXpCj.dpuf