Enzyme Reactions in Apples

Certain substances can impede chemical reactions. This can happen for various reasons. In the chemical reaction oxidation chemicals inside certain substances react with the oxygen in the air around them. For example fresh cut apples turn brown when the enzyme polyphenol oxidase inside the apple react with the oxygen in the air. Similar to when iron rusts. In our experiment we will test what happens when we attempt to impede the oxidation process in freshly cut apples. We hope to prove that an antioxidant such as lemon juice will stop the polyphenol oxidase from oxidizing the apple. In our experiment we will use two samples of apple. First we slice apples to expose them to the oxygen. Then we apply the anti oxidant lemon juice to one of our samples. As time elapses we examine the difference between our control and the apple we applied the lemon to. On the right we see the apple that has had lemon applied to it has not begun the oxidation process. Then on the left we see that the apple has been oxidized. We can conclude from this that the antioxidants in the lemon impeded the polyphenol oxidase in the apple on the right. While the apple on the left has completed the oxidation process, it's enzymes have reacted with the air causing a chemical reaction that we see as a browning of the apple. By Joni Miller, Alan Yedid and Ryan Sherman