6.2 Cooking With Vegetable Oils

Question 1

Why does food cool faster in oils than water?

Answer 1

Because oil has a higher boiling point

Question 2

Name 3 advantages to using oil to cook food instead of water

Answer 2

• cooks faster so uses less energy
• makes the flavour, colour, texture better
• some of the oil is absorbed so the energy content of the food increases

Question 3

Why is the energy we get from food cooked in oil higher than the energy we get from food cooked in water?

Answer 3

The oil is absorbed into the food so we get the energy from the oil in the food

Question 4

What is hydrogenation?

Answer 4

The hardening of unsaturated oils to become saturated oils

Question 5

How does hydrogenation work?

Answer 5

Unsaturated oils can be reacted with hydrogen so that some or all of the double carbon bonds can become single bonds to hydrogen atoms

Question 6

Describe the optimum conditions for hydrogenation

Answer 6

• 60*c

* using a nickel catalyst

Question 7

Why do the hydrogenated oils have higher melting points?

Answer 7

They are more saturated

Question 8

Why is hydrogenation also known as hardening?

Answer 8

By adding the hydrogen, this makes the hydrogenated oils solids at room temperature

Question 9

Name 2 uses of hydrogenated oils

Answer 9

• used as spreads

* to make things that require solid fats, like pastries and cakes

Question 10

What state are unsaturated oils at room temperature?

Answer 10

Liquid

Question 11

What is meant by hardening vegetable oils?

Answer 11

Reacting the unsaturated oils with hydrogen means they become hydrogenated oils which are solid at room temperature because their melting points increase

Question 12

Which vegetable oils are the best for us and which are the worst?

Answer 12

Best: polyunsaturated fats
Worst: hydrogenated fats

Question 13

Which boiling point is higher, water or oil?

Answer 13

Oils boiling point is higher