Make biofuels and foodstuffs, have a high energy content, provide nutrients
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What two methods can we extract vegetable oils by?
Pressing or distillation
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How does pressing to get vegetable oils work?
Collect seeds using harvester, crushed and pressed in factory to get oil, processed to make useful products
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How does distillation to get vegetable oils work?
Plants are put into water and boiled, oil and water evaporate together and are collected by condensing them, water and other impurities removed to give oil
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Give an example of where pressing is used.
Seeds of the **** plant
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Give an example of where distillation is used.
Lavender oils
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What do all vegetable oils have in common?
They contain hydrocarbons
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What are unsaturated oils?
Vegetable oils where the hydrocarbon chains contain a double carbon bond
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How can we detect if a vegetable oil has a double carbon bond?
If it decolourises bromine water
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What are the advantages of cooking with vegetable oils?
Vegetable oils can be used at much higher temperatures than boiling water because of their high boiling points
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What are the disadvantages of cooking with vegetable oils?
Its high boiling point increases the energy content of foods compared with boiling water
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What are the differences with using vegetable oil rather than boiling water?
Food cooks quicker, outside of food turns a different colour/becomes crispier, inside of food is softer
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Why are hydrogenated oils more useful than other oils?
Because they are solids at room temperature so they can be made into spreads to put on bread and can be used to make cakes/biscuits/pastries
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How do we make hydrogenated oils?
By hardening unsaturated vegetable oils
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Describe the process of hardening.
Reacted with hydrogen in a nickel catalyst at about 60 degrees Celsius, the hydrogen adds onto the double carbon bonds in the vegetable oil molecules
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What is an emulsion?
A mixture liquids that do not dissolve into each other- oil and water
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Give some example of emulsions.
Ice cream, mayonnaise, emulsion paints, salad dressings, milk, face creams, body lotions, lipsticks, lip gloss
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What is an emulsifier?
A substance which helps keep immiscible liquids mixed so that they do not separate out into layers, meaning the emulsion stays thick and smooth
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What does hydrophobic mean?
Not attracted to water
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What does hydrophilic mean?
Attracted to water
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Which part of an emulsifier is hydrophobic?
Tail (long hydrocarbon chain)
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Which part of an emulsifier is hydrophilic?
Head (group of atoms that carry a charge)
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How does an emulsifier work?
The hydrophobic tail dissolves in oil making tiny droplets, surface of each oil droplet is charged by hydrophilic head sticking out in water, as like charges repel, the oil droplets repel each other, keeping them spread out
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Give some examples of emulsifiers.
Mustard and egg yolk
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What is a food additive?
A substance that is added to food to preserve it or to improve its taste/texture/appearance
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What is an E number?
A number given to additives that have been approved in Europe
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Why are fatty foods more palatable and tempting to eat?
Because emulsifiers improve the texture of foods enabling water and oil to mix
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Why are vegetable oils healthier than animal fats?
Healthier for your heart, don't clog up blood vessels of heart
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Why are unsaturated fats in vegetable oils good for you?
Vitamin E, keep arteries clear, reduce risk of heart disease, lower level of bad cholesterol
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Why are fats used to cook chips bad?
Increase in heart disease
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Other cards in this set
Card 2
Front
Where do vegetable oils come from?
Back
Plants, such as oilseed ****
Card 3
Front
Why are vegetable oils useful?
Back
Card 4
Front
What two methods can we extract vegetable oils by?
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