Plant Oils

Question 1

Define ‘plant oil’

Answer 1

Oil extracted from a plant

Question 2

Some fruits and seeds contain a lot of ____

Answer 2

Some fruits and seeds contain a lot of oil

Question 3

Give 2 examples of fruits that contain a lot of oil

Answer 3

1. Avocados
2. Olives

Question 4

Give 2 examples of seeds that contain a lot of oil

Answer 4

1. Sesame
2. Peanuts

Question 5

What two things can plant oils be used for

Answer 5

1. Food
2. Fuel

Question 6

What are the 2 steps to getting the oil out of the plant material (but not seperating)

Answer 6

1. Crushing the plant material
2. Press the crushed plant material between two metal plates and squash the oil out

(pressing)

Question 7

Name the 2 ways oil can be separated from the crushed plant material

Answer 7

1. By using a centrifuge
2. By using solvents

Question 8

What is teh next step after separating oil from crushed plant material, and what does it do?

Answer 8

Distillation

Refines oil, and removes:

1. Water
2. Solvents
3. Impurities

Question 9

Name 3 advantages of using vegetable oil in food

Answer 9

1. Provide a lot of energy as have a high energy content
2. Other nutrients in vegetable oils
3. Contain fatty acids; needed for many metabolic processes

Question 10

What kind of nutrient do seed oils contain?

Answer 10

Vitamin E

Question 11

Name 3 benefits of using vegetable oils in cooking

Answer 11

1. Higher boiling points than water - can cook food at higher temp.s and faster* speeds
2. Gives food a different flavour
3. Using oil to cook food increases the energy we get from eating it

_{(on exam you have to put <strong>cooks faster</strong> as result of higher boilng point than water to get the mark)}

Question 12

Why do oils give foods a different flavour?

Answer 12

1. Oil gives its own flavour
2. Many flavours come from chemicals that are soluble in oil - the oil ‘carries’ the flavour, making it more intense

Question 13

Name 2 types of oil that can be processed and turned into fuels

Answer 13

1. Rapeseed
2. Soybean

Question 14

What makes vegetable oils so suitable for use as fuels?

Answer 14

They contain a lot of energy

Question 15

Name a particularly useful type of fuel made from vegetable oil

Answer 15

Biodiesel

Question 16

What makes biodiesel such a useful fuel?

Answer 16

It has similar properties to ordinary diesel - burns in the same way, so can use it to fuel a diesel engine (no modifications necessary)

Question 17

Why do we need to hydrogenate oils to use them as spreads?

Answer 17

They are usually liquids at room temperature

Question 18

Unsaturated oils contain which kind of carbon bond?

Answer 18

Double bonds between some of the carbon atoms in their carbon chains

Question 19

What do oils and fats contain?

Answer 19

Long-chain molecules with lots of carbon atoms

Question 20

Oils and fats are either ____ or ____

Answer 20

Oils and fats are either saturated or unsaturated

Question 21

What will unsaturated oil do to bromine water, and why?

Answer 21

Decolourise it from orange to colourless, because the bromine opens up the double bond and joins on

Question 22

How many carbon double bonds do monounsaturated fats contain?

Answer 22

One

Somewhere in their carbon chains

Question 23

How many carbon double bonds do polyunsaturated fats contain?

Answer 23

More than one

In their carbon chains

Question 24

What state are unsaturated vegetable fats at room temperature?

Answer 24

Liquid

Question 25

How do you harden/ hydrogenate unsaturated vegetable oils?

Answer 25

By reacting them with hydrogen in the presence of a nickle catalyst at a temp of 60^oC

Question 26

What happens during hydrogenation?

Answer 26

The hydrogen reacts with the double-bonded carbons and opens out the double bonds

Question 27

Hydrogenated oils have ____ ____ ____ than unsaturated oils, making them ____ ____ at room temperature.

Answer 27

Hydrogenated oils have higher melting points than unsaturated oils, making them more solid at room temperature

Question 28

How does being more solid at room temperature make hydrogenated oils more useful than unsaturated ones with baking?

Answer 28

Hydrogenated oils are useful as spreads for baking cakes and pastries

Question 29

Margarine is usually made from ____ hydrogenated vegetable oil.

Why?

Answer 29

Margarine is usually made from partially hydrogenated vegetable oil.

Turning all the double bonds to single bonds would make maragarine too hard and difficult to spread. Hydrogenating most of them gives margarine a nice, buttery, spreadable consistency.

Question 30

In what kind of food are partially hydrogenated vegetable oils usually used in instead of butter?

Answer 30

Processed foods

Question 31

For what 2 reasons are partially hydrogenated vegetable oils used in processed foods instead of butter?

Answer 31

1. They are cheaper - makes biscuits cheaper
2. They keep longer - gives them a longer shelf life

Question 32

Name a disadvantage of eating partially hydrogenateed vegetable oils

Answer 32

They contain a lot of ‘trans fats’

Evidence to suggest that trans fats are very bad for you

Question 33

Vegetable oils tend to be ____, while animal fats tend to be ____

Answer 33

Vegetable oils tend to be unsaturated, while animal fats tend to be saturated

Question 34

Why are saturated fats generally less healthy than unsaturated fats?

Answer 34

Saturated fats increase the amount of cholesterol in the blood, which can block up the arteries and increase the risk of heart disease

Question 35

Name an advantage of natural unsaturated fats such as olive oil and sunflower oil

Answer 35

They reduce the amount of blood cholesterol

Question 36

Explain why partially hydrogenated vegetable oils are worse for you than the natural ones

Answer 36

Partially hydrogenated vegetable oils contain trans fats which increase the amount of cholesterol in the blood, increasing the risk of heart disease

Question 37

Name a disadvantage to cooking food in any sort of vegetable oil

Answer 37

It makes the food more fattening