Fats and Oils

Key Words
1. Immiscible
  1. When two homogeneous mixtures do not form or mix when added together
2. Emulsion
  1. A stable mixture made up of lots of tiny droplets of one liquid (oil) suspended in another liquid (water)
3. Emulsifier
  1. A substance that can be added to an emulsion to make it more stable and stop it from separating out.
4. Hydrophilic
  1. Attracted to water (water loving)
5. Hydrophobic
  1. Attracted to oil or repelled by water (water hating)
6. Hydrogenation
  1. The addition of hydrogen to a compound, at 60 degrees centigrade with a nickel catalyst
7. Catalyst
  1. A substance that can speed up a reaction without being changed or used up in the reaction
Methods of how to extract plant oils
1. Steam Distillation
  1. Plant material is heated until the oils evaporate. The vapour is collected, cooled and condensed back into liquid. It is then filtered
  2. Our experiment:
    1. We ripped up the orange peel, put it in a test tube, filled it 2/3 with water, added anti-bumping granules, shook it, placed a bung on the testube with a delivery tube in, leading to another test tube, in a glass of icy water. The tube with orange in was lightly heated, but not boiled. The mixture began to evaporate and the steam went through the delivery tube, and then condensed in the icy tube. The oil collected was in a thin layer on top of the water. These were then separated
2. Pressing
  1. Plant material is crushed and this is then pressed between metal plates to squash the oil out. The oil is separated from the water and crushed plant material by centrifuge - spun around at high speeds, separating each food source
Saturation
1. Vegetable oils that are unsaturated contain double carbon bonds. These can be detected by reacting with bromine water
  1. The test for seeing if something is unsaturated (has double bonds), is if you add it to bromine water, it turns colourless
2. Types
  1. Saturated - no double bonds
  2. Monounsaturated - one double bond
  3. Polyunsaturated - many double bonds
    1. Effects the smoke point
How does oil change the properties of a food?
1. Vegetable oils have higher boiling points than water and so can be used to cook foods at higher temperatures than by boiling. This produces quicker cooking and different flavours but increases the energy that the food releases when it is eaten
2. Higher energy, crunchier texture, darker
Hydrogenation
1. Required Conditions
  1. Nickel Catalyst must be there, which speeds up the reaction without changing it. The temperature must be 60 degrees centigrade. And there has to be the presence of hydrogen
2. What is happening?
  1. Vegetable oils that are unsaturated (contain double bonds), can be hardened by reacting them with hydrogen. It becomes saturated
3. Diagram
4. The hydrogenated oils have higher melting points so they are solids at room temperature, making them useful as spreads and in cakes and pastries.
Emulsions
1. Products
  1. Salad dressings
  2. Ice cream
  3. Cosmetics
  4. Paint
  5. Milk
  6. Mayo & vinegar
2. What are they?
  1. Emulsions are thicker than oil or water and have many uses that depend on their special properties.
    1. They provide better texture, costing ability and appearance
Oil Sources
1. Lavender
2. Olive
3. Orange
4. Sunflower
5. Oil-seed Rape
6. Many plants produce useful oils and plant material is crushed and the oil removed by pressing or in some cases by distillation
Vegetable Oils
1. Vegetable oils are important foods and fuels as they provide a lot of energy
2. Do not dissolve in water
3. Can be used as fuels
Emulsifiers
1. These are added to an Emulsion so that the oil based substance mixes with the water based one
2. They have hydrophilic and hydrophobic properties
  1. Diagram
3. Egg yolk
4. Mustard

Next up

Fats and Oils

Description

Resource summary

Media attachments

Similar

	Created by slothysqump123 over 9 years ago