Question

The key enzyme involved in enzymatic browning of fruits and vegetables is
1. Peroxidase
2. Polyphenol oxidase
3. Catalase
4. Cholesterol oxidase

Answer 1

Correct Answer - Option 2 : Polyphenol oxidase

The correct answer is Polyphenol oxidase.

• Enzymatic browning 
  • Enzymatic browning is a chemical process that occurs in fruits and vegetables by the enzyme polyphenol oxidase, which results in brown pigments.
• Enzymatic browning is detrimental to quality, particularly in post-harvest storage of fresh fruits, juices, and some shellfish. 
• Polyphenol oxidase is also known as PPO and chloroplastic.
• PPO is a tetramer that contains four atoms of copper per molecule, and binding sites for two aromatic compounds and oxygen.
• PPO may accept monophenols and o-diphenols as substrates.

• Peroxidases are also known as peroxide reductases.
  • They are a large group of enzymes that play a role in various biological processes.
• Catalase is a common enzyme found in nearly all living organisms exposed to oxygen which catalyzes the decomposition of hydrogen peroxide to water and oxygen.
• A cholesterol oxidase is an enzyme that catalyzes the chemical reaction in enzymology.