Question

Enzymatic browning in cut apples is primarily caused by which enzyme?

• A. Amylase
• B. Polyphenol oxidase
• C. Protease
• D. Lipase

Hint:

To reduce browning in apples, you can reduce oxygen exposure (e.g., by soaking in lemon juice) to slow the activity of polyphenol oxidase.

Answer 1

The Correct Option is B

When apples are cut or bruised, they often turn brown due to a chemical reaction known as enzymatic browning.
This process is catalyzed by the enzyme polyphenol oxidase (PPO), also known as tyrosinase.
PPO reacts with oxygen and phenolic compounds naturally present in plant tissues, leading to the formation of brown-colored melanins.
This reaction serves as a defense mechanism in plants but is undesirable in fruits like apples for aesthetic and quality reasons.
Let’s consider why the other enzymes are incorrect:
- Amylase breaks down starch into sugars and is not involved in browning.
- Protease digests proteins and has no role in this context.
- Lipase breaks down fats into fatty acids and glycerol. Again, not involved in browning.
Thus, the correct enzyme causing browning in apples is polyphenol oxidase.