Plant Oils Flashcards
Some [ ] and [ ] contain a lot of oil
Plants and seeds
What can plant oil be used for?
Food or fuel
How can oil be extracted from plants? (Traditional method)
1) The plant material is crushed
2) Press the crushed plant material between metal plates and squash the oil out
What does distillation do?
Refines oil, and removes water, solvents and impurities
Apart from crushing, how else can you get oil from plants?
Using solvents
How is oil separated fro crushed plant material?
A centrifuge
Why are vegetable oils used in food?
1) Provide a lot of energy - high energy content
2) There are other nutrients in vegetable oils
3) vegetable oils contain essential fatty acids, which the body needs for many metabolic processes
Why are vegetable oils used in fuel?
1) They provide a lot of energy
Why is a very useful fuel made from vegetable oils? Describe it.
Biodiesel - has similar properties to ordinary diesel - it burns the same way, so you can use it to fuel a diesel engine
What do unsaturated oil contain?
C=C bonds
What type of molecules do oils and fats contain?
Long-chain molecules with lots of carbon atoms
Oils and fats can either be [ ] or [ ]
Saturated or unsaturated
What will an unsaturated fat do to bromine water
Make the bromine water turn colourless - decolourise it
What are monounsaturated fats?
Fats that contain ONE C=C double bond somewhere in their carbon chains
What are polyunsaturated fats?
Fats that contain MORE than one C=C double bond
Unsaturated oils can be [ ]
Hydrogenated
What state are vegetable oils at room temperature?
Liquid
What is hydrogenation?
Vegetable oils can be hardened by reaction them with hydrogen in the presence of a nickel catalyst at about 60 °C.
The hydrogen reacts with the double-bonded carbons ad opens out the double bonds
Can you draw the diagram for a hydrogenation reaction of ethene?
Answer page 61
What differences do hydrogenated oils have from normal oil? Why is that useful?
1) Higher melting points - therefore more solid at room temp. This makes them useful as spreads
Describe the hydrogenation of margarine
Usually made from partially hydrogenated vegetable oil - turning ALL the double bonds to single bonds would make the margarine too hard and difficult to spread
Why are partially hydrogenated vegetable oils used instead of butter in processed foods?
They are a lot cheaper than butter and they keep a lot longer
What is the disadvantage of partially hydrogenated vegetable oils?
You end up with a lot of trans fats. There’s evidence to suggest that trans fats are very bad for you.
Vegetables oils tend to be [ ], while animals fats tend to be [ ]
Vegetable: Unsaturated
Animal: Saturated
Which is unhealthier, saturated or unsaturated? Why?
Saturated fats (generally) - they increase the amount of cholesterol in the blood, which can block up the arteries and increase the risk of heart disease
Describe unsaturated fats in relation to cholesterol
Natural unsaturated fats reduce the amount of blood cholesterol. But because of the trans fats, partially hydrogenated vegetable oil increases the amount of cholesterol in the blood
What does cooking food in oil make the food?
More fattening
