Vegetable oils, emulsions and hydrogenation

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  • Created by: Heather
  • Created on: 28-05-14 11:36
Where are vegetable oils found?
THey are natural oils found in seeds, nuts and some fruits,
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How is the vegetable oils made from the seeds, nuts and some fruits?
It is crushed and pressed to squeeze the oil out and the impuritites are removed to leave pure vegetable oils,
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How is sunflower oil and other more difficult oils extracted?
After the plant material is crushed and pressed, The oils must be dissolved in a substance. Once it is dissolved, the solvent is remvoed by distillation and impurities removed to leave pure oils,
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What is a advantageous property of vegetable oils over water and what does this allow?
It has higher boiling points-This measn foods can be cooked and fried at higher temperatures,
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What are the advantages of cooking food in vegetable oil?
-Cooks faster than if they were boiled, -Turns brown and cripsy so they have different flavours, -It releases more energy,
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What does it mean if vegetable oils are saturated? What do they tend to be at room temperature and an example?
They have single bonds between carbon atoms. They tend to be solds at room temperature-Lard is an example,
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What does it mean if some vegetable oils are unsaturated? What do they tend to be at toom temperature?
They have double bonds between carbon atoms. They are usually liquid at room temperature,
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In unsaturated fats and oils, that are the two categories for the fats and what does it mean?
-Monounsaturated fats-One double bond in eahc fatty acud, -Polyunsaturated fats-Many double bonds,
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what is an emulsion?
If oils and water are shaken together,tiny droplets of one liquid spread through the other liquid, forming a mixture called an emulsion,
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Wht are emulsions useful in food?
As they are thicker and more viscous than the oil or water they contain,
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What are some examples of where emulsions are used?
Cosmetics, paints and salad dressings and icecream,
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What are the two main types of emulsions invoolving oil and water?
Oil droplets in water-Milk, ice cream, salad cream, mayonnaise, Water droplets in oil-Margarine, butter, skin cream, moisturising lotion,
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What are emulsifiers and an example?
Subustances that stabilise emulsions and stop them from spreading out. An eexample if egg yolk,
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Describe the structure of an emulsifier and what it does?
-A hydrophilic head that forms chemical reactions with water and not oils, -A hydrophobic tail that forms chemical bonds with the oil and not water so unable to seperate,
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What is hydrogenation?
When breaking the double bonds of staurated vegetable fats to single bonds by reacting it with hydrogen,
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What are the conditions needed?
Hydrogen gas, -60oC, -a nickel catalyst,
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Other cards in this set

Card 2

Front

How is the vegetable oils made from the seeds, nuts and some fruits?

Back

It is crushed and pressed to squeeze the oil out and the impuritites are removed to leave pure vegetable oils,

Card 3

Front

How is sunflower oil and other more difficult oils extracted?

Back

Preview of the front of card 3

Card 4

Front

What is a advantageous property of vegetable oils over water and what does this allow?

Back

Preview of the front of card 4

Card 5

Front

What are the advantages of cooking food in vegetable oil?

Back

Preview of the front of card 5
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