1.6 Plant Oils and Their Uses

Question 1

How is oil extracted from fruits/seeds/nuts?

Answer 1

1. The plant material is crushed.
2. The crushed plant material is pressed between metal plates
3. Distillation refines oil, water, solvents and impurities are removed

Question 2

Why are vegetable oils important? (3)

Answer 2

1. They provide a lot of energy, nutrients and fatty acids
2. They have higher boiling points than water so they can be used to cook food at higher temperatures and faster
3. Cooking with vegetable oil gives a different flavour

Question 3

What do unsaturated vegetable oils contain and how is this tested for?

Answer 3

C=C bond. Reacting an unsaturated vegetable oil with bromine water will turn it from orange to colourless

Question 4

How can unsaturated vegetable oils be hardened?

Answer 4

Hydrogenation. Reacting them with hydrogen in the presence of a nikel catalyst at about 60ºC

Question 5

What is hydrogenated unsaturated oils used for and why?

Answer 5

They’re used for margarine because hydrogenating oils increases the melting point so that it is a solid at room temperature

Question 6

What is an emulsion?

Answer 6

A mixture of oil and water. One liquid is suspended in the other

Question 7

Give some uses of emulsions (4)

Answer 7

• Food
• Ice creams
• Moisturising lotions
• Paints

Question 8

What is an emulsifier?

Answer 8

A molecule that is half attracted to water (hydrophilic) and half attracted to oil (hydrophobic)

Question 9

The head of an emulsifier molecule is hydro…

Answer 9

philic

Question 10

The tail of an emulsifier molecule is hydro…

Answer 10

phobic

Question 11

What are emulsifiers used for?

Answer 11

To stop emulsions from seperating out, making the emulsion last longer