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Flashcards in Plant Oils Deck (37):
1

Define 'plant oil'

Oil extracted from a plant

2

Some fruits and seeds contain a lot of ____

Some fruits and seeds contain a lot of oil

3

Give 2 examples of fruits that contain a lot of oil

1. Avocados

2. Olives

4

Give 2 examples of seeds that contain a lot of oil

1. Sesame

2. Peanuts

5

What two things can plant oils be used for

1. Food

2. Fuel

6

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

1. Crushing the plant material

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

(pressing)

7

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

1. By using a centrifuge

2. By using solvents

8

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

Distillation

Refines oil, and removes:

1. Water

2. Solvents

3. Impurities

9

Name 3 advantages of using vegetable oil in food

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

10

What kind of nutrient do seed oils contain?

Vitamin E

11

Name 3 benefits of using vegetable oils in cooking

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 cooks faster as result of higher boilng point than water to get the mark)

12

Why do oils give foods a different flavour?

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

13

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

1. Rapeseed

2. Soybean

14

What makes vegetable oils so suitable for use as fuels?

They contain a lot of energy

15

Name a particularly useful type of fuel made from vegetable oil

Biodiesel

16

What makes biodiesel such a useful fuel?

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

17

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

They are usually liquids at room temperature

18

Unsaturated oils contain which kind of carbon bond?

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

19

What do oils and fats contain?

Long-chain molecules with lots of carbon atoms

20

Oils and fats are either ____ or ____

Oils and fats are either saturated or unsaturated

21

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

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

22

How many carbon double bonds do monounsaturated fats contain?

One

Somewhere in their carbon chains

23

How many carbon double bonds do polyunsaturated fats contain?

More than one

In their carbon chains

24

What state are unsaturated vegetable fats at room temperature?

Liquid

25

How do you harden/ hydrogenate unsaturated vegetable oils?

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

26

What happens during hydrogenation?

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

27

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

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

28

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

Hydrogenated oils are useful as spreads for baking cakes and pastries

29

Margarine is usually made from ____ hydrogenated vegetable oil.

Why?

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.

30

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

Processed foods

31

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

1. They are cheaper - makes biscuits cheaper

2. They keep longer - gives them a longer shelf life

32

Name a disadvantage of eating partially hydrogenateed vegetable oils

They contain a lot of 'trans fats'

Evidence to suggest that trans fats are very bad for you

33

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

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

34

Why are saturated fats generally less healthy than unsaturated fats?

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

35

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

They reduce the amount of blood cholesterol

36

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

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

37

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

It makes the food more fattening