KS3 Enzymic Browning

Enzymic browning occurs when...

• enzymes are damaged and oxidation takes place

• Fruit is spoiled and unsafe to eat

• Fruit goes mouldy

• Food gets bacteria on it and makes your enzymes go brown

Organize these foods into the right categories

Groups:

(a) Fruit

,

(b) Vegetables

• Celery

• Swede

• Mushrooms

• Peas

• Apple

• Pear

• Watermelon

• Tomatoes

• Carrots

• Cucumber

This antioxidant is often used in fruit salads in the form of orange juice to prevent enzymic browning.

• Vitamin C

• Protein

• Fat

• Calcium

Match the following sentences...

• acid, heat or water.

• Polyphenol oxidase is an

• enzyme.

• Enzymic browning can be prevented by

• polyphenol oxidase

• Enzymes are

• the oxygen reacts with the enzymes.

• The enzyme in fruit that causes fruit to go brown is called

• catalysts that speed up reactions.

• Pigmentation occurs when fruit browns because

Enzymic browning is a ...

• Biological reaction

• Emotional reaction

• Chemical Reaction

• Allergic reaction

Match the following

• enzymes react with oxygen in the air and oxidation takes place.

• The enzyme in fruit which causes it to go brown is...

• Polyphenol Oxidase

• When the cell of a fruit is cut open,

• they speed up chemical reactions

• Apples, potatoes, avocados, bananas and aubergines are fruits and vegetables...

• that are commonly affected by enzymic browning

• Enzymes are catalysts...

• a chemical reaction that causes fruit do go brown when exposed to oxygen

• Enzymic browning is...

To prevent enzymic browning you can use an acid such as...

• Water

• Apple juice

• Lemon juice

• Bicarbonate of soda

Fruits and vegetables that are affected by enzymic browning shouldn't be stored in...

• Metal containers

• Plastic containers

• Glass bowls

• Paper plates

Polyphenol oxidase is an ..... this acts as a catalyst and speeds up reactions.

This type of cooking method can prevent enzymic browning...

• Boiling

• Roasting

• Blanching

• Grilling

Answer explanation

By plunging fruit and vegetables into boiling hot water for a short amount of time it denatures the protein. Then plunging them into ice cold water after draining from the hot water you can stop the cooking process and retain the vegetables colour, crunch and flavour.