C1.6 Plant oils and their uses

Question 1

How are oils extracted from plants?

Answer 1

The plants are crushed and the oil removed through pressing or distillation

Question 2

How is oil separated from crushed plant material?

Answer 2

By a centrifuge or solvents

Question 3

What does distillation do to the oil extracted from plants?

Answer 3

It removes water, solvents and impurities

Question 4

Examples of fruits rich in oil

Answer 4

Avocados and olives

Question 5

Examples of seeds rich in oil

Answer 5

Brazil nut, peanuts and sesame seeds

Question 6

What can plant oils be used for?

Answer 6

Food or for fuel

Question 7

What is the traditional method of producing olive oil?

Answer 7

The olive is crushed. The crushed olive is then pressed between metal plates and the oil is squashed out

Question 8

Vegetable oils provide a lot of

Answer 8

Energy

Question 9

Oil from seeds contain

Answer 9

Vitamin E

Question 10

Vegetable oils contain essential

Answer 10

Fatty acids

Question 11

Why are vegetable oils good for cooking?

Answer 11

They have higher boiling points than water which means they cook at higher temperatures and faster speeds

Question 12

Why does cooking with oil give food a different flavour?

Answer 12

Because many of the flavours come form chemicals which are soluble in oil, meaning the oil carries the flavour

Question 13

What does using oil increase when cooking?

Answer 13

The amount of energy we get from the food

Question 14

Give examples of vegetable oils which can be processed and turned into fuels

Answer 14

Rapeseed oil and soybean oil

Question 15

What do vegetable oils provide lots of which makes them good as fuels?

Answer 15

Energy

Question 16

Which particularly useful fuel is made from vegetable oil?

Answer 16

Biodiesel

Question 17

What kind of bonds do unsaturated oils have?

Answer 17

Double

Question 18

What happens to bromine water when an unsaturated oil/fat is present?

Answer 18

It will decolourise

Question 19

How can unsaturated oils be hardened?

Answer 19

By reacting them with Hydrogen

Question 20

What is the name of the process when unsaturated oils are hardened?

Answer 20

Hydrogenation

Question 21

What is the process of hydrogenation?

Answer 21

The unsaturated vegetable oils are reacted with hydrogen with the presence of a nickel catalyst at about 60 degrees celsius. The hydrogen reacts with the double-bonded carbons and opens out the double bonds

Question 22

Why are vegetable oils hardened for use in foods?

Answer 22

Hydrogenated oils have higher melting points than unsaturated oils, so they are more solid at room temperature. This makes them useful for spreads, baking cakes and pastries

Question 23

Is margarine hydrogenated?

Answer 23

No, it is partially hydrogenated to make it easier to spread

Question 24

How many double bonds does a monounsaturated fat contain?

Answer 24

One

Question 25

How many double bonds does a polyunsaturated fat contain?

Answer 25

More than one

Question 26

Why are partially hydrogenated oils used over butter in processed foods?

Answer 26

The oils are a lot cheaper and they keep longer

Question 27

What is a disadvantage of partially hydrogenated oils?

Answer 27

It results in a lot of trans fats which are meant to be very bad for you

Question 28

Vegetable oils tend to be

Answer 28

Unsaturated

Question 29

Animal fats tend to be

Answer 29

Saturated

Question 30

Are unsaturated fats healthier or less healthy than saturated fats?

Answer 30

Healthier

Question 31

Unsaturated fats reduce

Answer 31

Blood cholesteral

Question 32

Partially hydrogenated vegetable oils increase

Answer 32

Blood cholesteral

Question 33

Saturated fats increase

Answer 33

Blood cholesteral

Question 34

Cooking with oil makes it more

Answer 34

Fattening

Question 35

Oils do not

Answer 35

Dissolve in water

Question 36

What is an emulsion?

Answer 36

Emulsions are made up of lots of droplets of one liquid suspended in another liquid. E.g. oil and water, you can have an oil-in-water emulsion or a water-in-oil emulsion

Question 37

How do emulsions compare to oil and water?

Answer 37

They are thicker

Question 38

Give an example of an emulsion

Answer 38

Mayonnaise is an emulsion of sunflower oil (or olive oil) and vinegar

Question 39

How can emulsions be used in food?

Answer 39

They can be used as salad dressings and in sauces. E.g. a salad dressing made by the emulsion of olive oil an vinegar coats salad better than plain oil or vinegar. They can also be used in ice creams and whipped cream.

Question 40

Advantages of emulsifiers

Answer 40

They provide better texture, coating ability and appearance

Question 41

How else can emulsions be used?

Answer 41

In moisturising lotions, it's easier to rub into the skin. other examples include cosmetics and paints

Question 42

Oil and water naturally

Answer 42

Seperate

Question 43

What is the structure of an emulsifier molecule?

Answer 43

On part is attracted to water and the other part is attracted to oil/fat

Question 44

Which part of the emulsifier molecule is attracted to water?

Answer 44

The HydroPHILIC end of the molecule which latches onto water molecules

Question 45

Which part of the emulsifier molecule is attracted to oil?

Answer 45

The HydroPHOBIC end of the molecule which latches onto oil molecules

Question 46

What happens when you shake water an oil together?

Answer 46

The oil forms droplets surrounded by a coat of emulsifier

Question 47

Which part of the emulsifier molecule is facing outwards?

Answer 47

The HydroPHILIC end

Question 48

Why doesn't the oil try to join with the other oil droplets and separate?

Answer 48

Because the oil droplets are repelled by the hydrophilic bit of the emulsifier facing outwards while the water molecules attach to the hydrophilic end. Meaning the two cannot separate out

Question 49

Pros of emulsifiers

Answer 49

Gives products a longer shelf life. Allows companies to produce food lower in fat but still has a good texture

Question 50

Cons of emulsifiers

Answer 50

Some people are allergic to certain emulsifiers