The Science Behind the Browning of Apples and How to Prevent It

Ever noticed that the inside of an apple changes color when exposed to air? This is due to a process known as enzymatic browning. This article explores the science behind this phenomenon and offers tips to prevent it.

Understanding Enzymatic Browning in Apples

When an apple is cut or damaged, the cellular walls are broken down, releasing phenolic compounds. These compounds, when exposed to oxygen, react with an enzyme called polyphenol oxidase (PPO) to form brown pigments called melanins. This process is known as enzymatic browning.

Step-by-Step Guide to Enzymatic Browning in Apples

Step 1: Cell Damage

When an apple is cut, the cells are damaged. This damage results in the release of phenolic compounds from the ruptured cells.

Step 2: Enzyme Reaction

The exposed polyphenol oxidase (PPO) enzyme reacts with these phenolic compounds in the presence of oxygen. This reaction creates melanins, which are responsible for the browning of the apple.

Step 3: Color Change

As these melanins accumulate, the flesh of the apple turns brown. This process is similar to what happens in other fruits and vegetables like bananas and avocados.

Preventing Apples from Browning

While enzymatic browning is a natural phenomenon, there are several methods to slow down this process:

Method 1: Applying Lemon Juice

Lemon juice contains ascorbic acid, which can help to inhibit the PPO enzyme. By applying lemon juice to the cut surface of the apple, you can prevent it from browning.

Method 2: Sealed Container

Place the cut apple in a sealed container to minimize exposure to air. Air can facilitate the reaction, so reducing the exposure can slow down the browning process.

Method 3: Refrigeration

Refrigerating the apple can lower the temperature, which slows down the chemical reactions involved in browning. Keeping the apple cold should help to maintain its natural color.

Genetically Engineered Brown-Resistant Apples

Recently, there has been an attempt to introduce genetically engineered apples that do not go brown when sliced. However, the growers hesitate to label these apples as GMOs due to consumer concerns. Instead, they emphasize the benefits and invite consumers to "Like them apples."

Checking Out Enzymatic Browning

To better understand the process, you can watch a short, 2-minute video that explains why sliced apples turn brown. The video uses a fun, interactive approach, inspired by the story of Masha and the Bear. This method makes learning about the science behind the browning of apples more engaging and accessible.

The process of browning in apples is essentially oxidation. When the apple is exposed to oxygen, it undergoes a chemical reaction involving the PPO enzyme, which turns it brown. This is akin to how hair color fades when it oxidizes. Understanding this can help you appreciate the importance of proper storage and handling of apples to maintain their freshness and appearance.

By understanding and managing the process of enzymatic browning, you can enjoy apples in their fresh and vibrant state, adding a delightful touch to your meals and snacks.