AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Hodder Education Revision Lessons Plant oils and their uses Click to continue

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Overview Many plants produce useful oils that can be converted into consumer products including processed foods. Emulsions can be made and have a number of uses. Vegetable oils can be hardened to make margarine. Biodiesel fuel can be produced from vegetable oils. Click to continue

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Plant oils and their uses 1 Some fruits, seeds and nuts are rich in oils that can be extracted. The plant material is crushed and the oil removed by pressing. Alternatively, the oil is dissolved in a solvent such as hexane and then the solvent is distilled off leaving the oil behind. Water and other impurities are removed. Click to continue What is meant by cold-pressed virgin olive oil?

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Plant oils and their uses 2 Why isn’t oil extracted from the leaves of plants? Click to continue Plant oil What part of the plant does the oil come from? Olive oilFruit Rape oilSeeds Peanut oilNut (food store for seeds) Avocado oilFruit Jojoba oilSeed Palm oilFruit

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Plant oils and their uses 3 Vegetable oils are important foods and fuels because they provide a lot of energy. They also provide us with nutrients. Click to continue carpathian/Fotolia What nutrients do plant oils contain?

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Plant oils and their uses 4 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 it increases the energy that the food produces when it is eaten. Click to continue Liaurinko/Fotolia Viktor/Fotolia Why are you more likely to put on weight if you eat a lot of chips than if you eat boiled potatoes?

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Emulsions 1 Oils do not dissolve in water. They can be used to produce emulsions — tiny droplets of oil suspended in water. Emulsions are thicker than oil or water and have many uses that depend on their special properties. Click to continue What uses do emulsions have?

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Emulsions 2 Emulsions provide better texture, coating ability and appearance, for example in Click to continue salad dressings ice creams cosmetics paints Emulsifiers have hydrophilic and hydrophobic properties.

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Emulsifiers Emulsifiers are used to make emulsions stable. They have hydrophilic (water loving) and hydrophobic (water hating) properties. Click to continue Explain how emulsifiers work.

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Saturated and unsaturated oils 1 Unsaturated vegetable oils contain carbon–carbon double bonds. They are sometimes called polyunsaturated fats. Click to continue Unsaturated fats can be detected by reacting with bromine water. Bromine water turns from orange-brown to colourless when it reacts with unsaturated fats.

AQA GCSE Science & Additional Science Chemistry 1 Topic 6 Saturated and unsaturated oils 2 Unsaturated vegetable oils 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 so they are solids at room temperature, making them useful as spreads and in cakes and pastries. What hydrogenated oils are there? Click to continue