List 3 things that plant oil can be extracted from.
Fruit, seed and nut
How are plant oils extracted?
Pressing or steam distillation
Why are plant oils used in foods?
Provide energy and nutrients
Why are plant oils used as fuels?
Give out energy but are renewable
Why are vegetable oils used in cooking?
Higher boiling points so cook food at a higher temperature and so faster
What is the disadvantage of cooking with vegetable oils rather than water?
Increases the energy content of the food
Give benefits, drawbacks and risks for using vegetable oils to produces fuels like biodiesel
No modification of engine needed
Can be mixed with ordinary diesel
Less polluting as carbon neutral
Biodegrades
But lot of land is used instead of for food
Also increased use of fertilisers and GM crops
Why does biodiesel produces no carbon dioxide overall?
Carbon dioxide used in photosynthesis is released during burning
Do oils dissolve in water?
No
What is an emulsion?
Mixture of 2 immiscible liquids
What special properties do emulsions have?
Thicker texture, coating ability and better appearance
What do emulsifiers do?
Stop the emulsion from separating
Draw and label an emulsifier.
How does an emulsifier work?
The Hydrophilic head is attracted to the water and the hydrophobic tail is attracted to the oil
What does hydrophilic mean?
Attracted to water
What does hydrophobic mean?
Attracted to oil
Give a disadvantage of using emulsifiers?
People could be allergic to additives
Vegetable oils are unsaturated what does this mean?
Contains double bonds
How can unsaturation be tested for?
Bromine water goes colourless
What 3 things are needed to harden vegetable oils?
Hydrogen, nickel catalyst, 60⁰C
What is the process of hardening vegetable oil called? Why?
Hydrogenation
How does hardening vegetable oils change the melting points?
Makes them higher as solid at room temperature
Give 2 uses of hardened vegetable oils.
Cakes and pastries and as spreads
Too much dietary fat and not enough exercise can lead to what?
Obesity
Give 2 problems that saturated fats can lead to?
Heart disease and stoke
