Plant Oils Flashcards
How is oil extracted from plants?
The plant material is crushed
Then the crushed plant material is pressed between metal plates squeezing the oil out
(Traditional way of producing olive oil)
How can oil be separated from crushed plant material?
By centrifuge (like a spin dryer)
Solvents can be used
Distillation can refine oil and remove water, solvents and impurities
Why are vegetable oils used in food?
They provide a lot of energy
They contain nutrients such as vitamin E
They contain fatty acids essential for many metabolic processes
What are the benefits of cooking with vegetable oil?
They have a high boiling point so can cook at faster speeds at higher temperatures
They add Flavour and increase the energy we get from it
Which vegetable oils can be used to produce fuels?
Rapeseed oil
Soybean oil
Why are vegetable oils used to produce fuels?
They’re suitable for fuels because they contain a lot of energy
A useful fuel made from plant oils is biodiesel (burns in the same way as diesel fuel so same engine can be used)
What type of bond do unsaturated oils contains?
C=C double bonds
What do oils and fats contain?
Long chain molecules with lots of carbon atoms
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
What are unsaturated vegetable oils at room temperate and how can they be hardened?
Liquid at room temp
They can be hardened by reacting them with hydrogen in the presence of a nickel catalyst at 60 degrees
Known as hydrogenation
The hydrogen reacts with double bonded carbons and opens out the double bond
What are the positives of hydrogenated oils?
They have higher melting points than unsaturated oils making them solid at room temp and better from spreading and cooking
What are partially hydrogenated vegetable oils?
Most of the double bonds are hydrogenated but not all
What is one positive and one negative of partially hydrogenated vegetable oils?
They last longer and are cheaper but
They produce a lot of trans fats and there’s evidence to suggest these are very bad for you
Why are saturated fats generally less healthy than unsaturated fats?
Saturated fats increase amount of cholesterol in your blood which can block arteries and risk heart disease
