Plant Oils and Their Uses - C1

Plant Oils and Their Uses - C1

1. Many plants produce useful oils

   • can be converted into consumer products
     • e.g. processed food

2. EMULSIONS

   • can be made and have a number of uses
   • oils don't dissolve in water
     • they can be used to produce EMULSIONS
       • = tiny droplets of oil suspended in water
   • thicker than oil or water
     • have many uses that depend on their special properties
   • provide better TEXTURE, COATING ABILITY and APPEARANCE
     • e.g. in salad dressings, ice creams, cosmetics and paints
   • emulsifiers have HYDROPHILIC and HYDROPHOBIC properties
     • EMULSIFIERS MAKE EMULSIONS STABLE
       • they have these properties:
         • HYDROPHILIC = water loving
         • HYDROPHOBIC = water hating

3. VEGETABLE OILS

   • can be hardened to make margarine
   • biodiesel produce from vegetable oils
   • important foods and fuels because they provide a lot of energy
   • higher boiling points than water
     • so can be used to cook foods at higher temperatures than boiling
     • produces quicker cooking and different flavours
       • increases energy that the food produces when eaten

4. some fruits, seeds and nuts are rich in oils

   • can be extracted
   • the plant material is crushed and the oil is removed by pressing
     • or, the oils is dissolved in a solvent e.g. hexane and the solvent is then distilled off leaving the oil behind
       • water and other impurities are removed

5. SATURATED and UNSATURATED OILS

   • UNSATURATED
     • contain CARBON-CARBON DOUBLE BONDS
       • they are sometimes called POLYUNSATURATED FATS
     • can be detected by REACTING with BROMINE WATER
       • BROMINE WATER TURNS FROM ORANGE-BROWN TO COLOURLESS WHEN IT REACTS WITH UNSATURED FATS
     • can be hardened to make them spreadable
       • by reacting them with HYDROGEN in the presence of a NICKEL CATALYST at about 60°c
         • HYDROGEN adds to the carbon-carbon double bonds
           • HYDROGENATED OILS have HIGHER MELTING POINTS
             • SOLIDS at ROOM TEMP
               • useful as spreads and in cakes and pastries

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