Properties Of Polysaccharides (Not Starch)

Question 1

Describe the properties of cellulose/dietary fibre

3

Answer 1

Dietary fibre is insoluble in water

It cannot be digested by the body, but it absorbs water as it passes through the intestinal tract and helps stimulate peristalsis

This is beneficial to the body as it speeds up the passage of food and waste, preventing bowel disorders e.g. constipation

Question 2

What is dietary fibre insoluble in?

Answer 2

Water

Question 3

What is the role of dietary fibre in digestion?

Answer 3

It cannot be digested by the body, but it absorbs water as it passes through the intestinal tract and helps stimulate peristalsis

Question 4

Dietary fibre helps stimulate peristalsis, what affect does this have on the body?

Answer 4

This is beneficial to the body as it speeds up the passage of food and waste, preventing bowel disorders e.g. constipation

Question 5

How does fibre prevent bowel disorders?

Answer 5

By speeding up the passage of food and waste through the body by stimulating peristalsis

Question 6

Describe the properties of gums

2

Answer 6

Gums are soluble in water

They have the ability to absorb large amounts of water to form a thick gel with a firm texture

Question 7

What are gums soluble in?

Answer 7

Water

Question 8

What can gums absorb large amounts of?

Answer 8

Water

Question 9

What is formed when a gum absorbs a large amount of water?

Answer 9

A thick gel with a firm texture is formed

Question 10

Give a culinary application of the gel formation property of gums
(1/2)

Answer 10

Salad dressings

Ice-cream

Question 11

Describe the properties of pectin

5

Answer 11

Pectin is naturally present in plant cells and the cell walls of fruit and vegetables

It is used as a setting agent, as it has the ability to absorb water to form a gel

It is only present in fruits when they are ripe

In under ripe fruits it is in the form of protopectin, and in overripe fruits it becomes pectic acid, neither of which can set as they cannot absorb water

For pectin to be extracted it needs heat and acid, e.g. lemon juice

Question 12

Where is pectin naturally present?

Answer 12

Pectin is naturally present in plant cells and the cell walls of fruit and vegetables

Question 13

What is the main use of pectin?

Answer 13

It is used as a setting agent

Question 14

Why is pectin used as a setting agent?

Answer 14

As it has the ability to absorb water to form a gel

Question 15

When is pectin present in fruits?

Answer 15

Only when they are ripe

Question 16

What form is pectin found as in under ripe fruits?

Answer 16

Protopectin

Question 17

What form is pectin found as in over ripe fruits?

Answer 17

Pectic acid

Question 18

Why cant protopectin or pectic acid be used as a setting agent?

Answer 18

As they cannot absorb water

Question 19

When is protopectin found in fruits?

Answer 19

When fruit is under ripe

Question 20

When is pectic acid found in fruits?

Answer 20

When fruit is over ripe

Question 21

How is pectin extracted from fruits?

Answer 21

Fruit needs to be heated and an acid such as lemon juice needs to be added