Plant oils Flashcards
How do you extract oil from a plant?
Crush the plant between metal plates and squash the oil out, then put in a centrifuge to separate from crushed plant material
Why are vegetable oils good for you?
They contain a lot of energy and vitamins, and they contain essential fatty acids
Why are vegetable oils good for cooking?
They have higher boiling points than water, they give a different flavour and they increase the energy we get from the food
Why are vegetable oils good fuels?
They have a lot of energy and can easily make biodiesel
What are unsaturated oils?
Long chain molecule with lots of carbon atoms with double bonds, monounsaturated has one double bond, polyunsaturated has more than one double bond
How can unsaturated oils be hardened?
By adding hydrogen to take up the double bonds in the presence of a nickel catalyst at about 60 degrees
What is made from hydrogenated oils and why?
Margarine partially because it gives it a spreadable consistency, and makes the oil cheaper and longer lasting, but produce bad fats
What are the health problems of oil?
Fats can block up the arteries and increase cholesterol
What are emulsions?
Mixtures of one liquid in another liquid
The more oil in an emulsion…
The thicker it is
How do emulsifiers work?
One end of them is attracted to water (hydrophilic) and the other to oil (hydrophobic) so they bond the two
What are the pros and cons of emulsifiers?
Pros are it stops food from separating out, gives them a longer shelf life and they are lower in fat but still have a good texture
Cons are some people are allergic to them eg. egg yolk
