Basics

• Apples are made up of cells called polyphenol oxidase. When those cells are exposed to oxygen, they catalyze and begin the browning process. This is the same reason a bruised apple has brown spots; its cells are damaged and have been exposed to oxygen, which browns the pigments in the apple’s flesh. The browning is harmless and safe to eat -- but it’s still an eyesore. Baking soda slows down the enzyme reaction rate, but apples might still turn slightly brown after long-term exposure to the air.

Factors

• Exposure to oxygen isn’t the only issue. Using a dull knife damages the apple cells more than a sharp one, and causes faster browning. Apple coring and cutting tools typically feature dull blades, which means that apples subjected to these implements might brown faster, too.

Using

• Concoct a baking soda solution to prevent apples from browning. Create a solution using 1 teaspoon for every 1/2 cup of water. Soak the sliced apples in the solution for a few minutes, then remove and store them in an airtight container in the refrigerator.

Alternatives

• Baking soda won’t alter the taste of the apples as long as the proper ratio is used. An alternative is to slice apples in cold water. This prevents oxidation and the subsequent browning process. Or brush apple slices with lemon, lime or another citrus acid to delay browning. Storing apples in cold environments, such as the refrigerator, helps slow down browning, too.