How an apple’s browning is affected depending on the preservative used.

In my experiment, I’m testing to see how different preservatives on an open-cut apple influence the rate at which it browns. My control group is going to be an apple with no preservative on it. I will also be testing for sugar, lemon juice, and salt. My hypothesis is that if I apply different forms of preservatives to an “exposed” (open) apple, then the most acidic/concentrated solution, salt, will preserve it the best because it delays the activation of the chemical reaction from the oxygen. I will be recording my observations in 10-minute increments.