Why Do Apples Turn Brown?

The video explains why apples turn brown when cut or damaged, focusing on the role of the enzyme polyphenol oxidase (PPO) which oxidizes phenols, leading to melanin production. This process is a natural immune response in plants to protect against infection. The browning is similar to the oxidation process that gives flavor to foods like cocoa and coffee.

What is the initial problem discussed regarding apples?

• They are too hard to bite.

• They are too sour.

• They turn brown and unappetizing.

• They are too sweet.

What enzyme is responsible for the browning of apples?

• Polyphenol oxidase

• Lipase

• Protease

• Amylase

What compound does polyphenol oxidase interact with to cause browning?

• Carbohydrates

• Lipids

• Proteins

• Phenols

What pigment is produced as a result of the oxidation of phenols?

• Melanin

• Xanthophyll

• Carotene

• Chlorophyll

Which of the following foods also undergoes a similar oxidation reaction to develop its flavor?

• Rice

• Potatoes

• Cocoa

• Bananas