C1.6 Plant oils and their uses
Many plants produce useful oils that can be converted into food products and fuels (e.g. biodiesel).
Candidates should use their skills, knowledge and understanding to:
■ evaluate the effects of using vegetable oils in foods and the impacts on diet and health (i.e. high-energy content of food, health benefits of unsaturated vs. saturated fats, and the effects of cooking foods in oil)
■ evaluate the use, benefits, drawbacks and risks of emulsifiers in foods.
Assessment and practical opportunities
■ pressing nuts (eg walnuts) between paper towels and studying the grease marks
■ steam distillation of lavender oil, orange oil, lemon oil, olive oil, rapeseed oil or vegetable oil
■ simple calorimetery investigations using small spirit burners or bottle tops to measure the energy released from various oils (weigh before and after, and measure the temperature change for a known mass of water)
■ making emulsions, eg oil/water, oil/vinegar
■ design and carry out an investigation into the effect of emulsifiers on the stability of emulsions
■ using bromine water to test fats and oils for unsaturation, eg testing sunflower oil against butter (using colorimeter to measure level of unsaturation).