Science Fair Project Research Paper: An Apple a Day Keeps the Dr. Away, but What Keeps the Apple from Turning Brown?
An Apple a Day Keeps the Dr. Away , but What Keeps the Apple from Turning Brown ? What causes apples to turn brown? Apples turn brown when they are cut or bruised because their plant tissue becomes exposed to the air. When this happens an enzyme that is found in apple tissue, called polyphenol oxidase, reacts to the oxygen in the air and oxidizes the phenolic compounds to o-quinones. The o-quinones are what create the brown color by forming amino acids ( McLandsborough, 2017 ). The amount of polyphenol oxidase varies from fruit to fruit. The type of apple, as well as the maturity of the apple, make a difference in the amount of this enzyme the fruit has. Growing conditions can also affect the amount of this enzyme an apple contains. The lower the level of polyphenol oxidase, the less likely the apple is to brown after being cut. Similarly, potatoes contain an enzyme called catechol which reacts with the oxygen in the air to turn the flesh of the potato brown as well. With both ...