Revision Guide - Plant Oils

Question 1

What bonds do unsaturated oils contain?

Answer 1

C=C double bonds

Question 2

What sort of molecules do oils and fats contain?

Answer 2

Long-chain molecules with lots of carbon atoms

Question 3

Are oils and fats saturated or unsaturated?

Answer 3

They can be either

Question 4

What bonds do unsaturated oils contain?

Answer 4

Double bonds between some of the carbon atoms in their chains

Question 5

What will unsaturated oils do to bromine water?

Answer 5

decolourise it

Question 6

What bonds to monounsaturated oils contain?

Answer 6

ONE C=C double bond somewhere in their carbon chains

Question 7

What bonds to polyunsaturated oils contain?

Answer 7

More than one C=C double bond

Question 8

How can unsaturated oils be hardered? How does this work?

Answer 8

By hydrogenation

Reacting them with hydrogen over a nickel catalyst at about 60 degreesC

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

Question 9

How are hydrogenated oils useful? why?

Answer 9

They can be useful as spreads for baking

→ Because they have higher melting points than unsaturated oils so they’re more solid at room temperature

Question 10

What is used instead of butter in processed foods? Why?

Answer 10

Partially hydrogenated vegeatable oils

→They’re a lot cheaper than butter and they keep longer

Makes the food cheaper and have a long shelf life

Question 11

What do partially hydrogenated vegetable oils contain?

Answer 11

Trans fats - which can be very bad for you?

Question 12

Whats healthier: saturated or unsaturated fats? Why?

Answer 12

Saturated fats are less healthy, as they incease the amount of cholesterol in the blood, which can block up the arteries and increase the risk of heart disease

Question 13

What can reduce the amount of blood cholesterol?

Answer 13

Natural unsaturated fats

Question 14

What can increase the amount of blood cholesterol?

Answer 14

Saturated fats

And partially hydrogenated vegetable oil

Question 15

What does cooking food in oil do? heath wise

Answer 15

Makes it more fattening

Question 16

What are emulsions made of?

Answer 16

Lots of droplets of one liquid suspended in another liquid

Question 17

The more oil you have in an oil-in-water emulsion..

Answer 17

The thicker it is

Question 18

Some oil-in-water emulsions?

Answer 18

Milk

Whipped cream

Ice cream

Question 19

Non-food emulsion uses?

Answer 19

Body lotions - the smooth textures make it easy to rub into the skin

Question 20

What are emulsifiers?

Answer 20

Molecules with one part thats attracted ti warer and another part thats attracted to oil or fat

Question 21

In an emulsifier; what is the part thats attarcted to water called?

Answer 21

Hydrophilic

Question 22

In an emulsifier; what is the part that is attracted to oil called?

Answer 22

Hyrophobic

Question 23

Pro’s and cons of emusifiers?

Answer 23

✓ They stop emulsions from sepearating out

✓ Gives them a long shelf life

✓ Allow food companies to produce food thats lower in fat but still have a food texture

✗ Some people are allergic to certain emulsifiers