Understanding Apple Browning and Enzyme Reactions

The video explains why apples turn brown when cut or damaged, focusing on the role of the enzyme polyphenol oxidase (PO) 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 that gives color and taste to foods like cocoa and coffee. The video concludes with a call to action for viewer engagement.

What is the main cause of disappointment when biting into an apple that looks delicious?

• The apple is too hard to bite.

• The apple is too sour.

• The apple is not juicy enough.

• The apple is brown and gross inside.

What enzyme is responsible for the browning of apple flesh?

• Polyphenol oxidase

• Amylase

• Lipase

• Protease

What does polyphenol oxidase (PO) do to phenols in fruits?

• It breaks them down into sugars.

• It encourages them to bond with oxygen atoms.

• It converts them into proteins.

• It makes them more acidic.

What pigment is produced as a result of phenol oxidation in fruits?

• Xanthophyll

• Melanin

• Carotene

• Chlorophyll

In what parts of human tissue is melanin primarily produced?

• Hair, eyes, and bottom layer of skin

• Liver, kidneys, and heart

• Muscles, tendons, and ligaments

• Nails, teeth, and bones

What is the purpose of melanin production in plant tissue?

• To enhance photosynthesis

• To protect against UV radiation

• To surround and slow down infections

• To attract pollinators

What happens when an apple is cut and exposed to air?

• It becomes sweeter.

• It starts to ferment.

• It becomes more acidic.

• It browns quickly due to oxidation.

Why do apple slices brown faster when served with crackers and cheese?

• They are kept at a higher temperature.

• They are exposed to air and oxygen.

• They absorb moisture from the air.

• They react with the cheese.

Which of the following foods also undergoes a similar oxidation reaction as apples?

• Cocoa

• Carrots

• Bananas

• Potatoes

What is a positive outcome of the oxidation reaction in foods like coffee and tea?

• It makes them more nutritious.

• It increases their shelf life.

• It enhances their color and taste.

• It makes them less acidic.