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Science

Vegetable oils, emulsions and hydrogenation

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Vegetable oils are obtained from plants. They are important ingredients in many foods, and can be hardened through a chemical process to make, for example, margarine. They can also be used as fuels, for example as biodiesel. Emulsifiers are food additives that prevent oil and water mixtures in food from separating.

Vegetable oils

Vegetable oils are natural oils found in seeds, nuts and some fruit. These oils can be extracted. The plant material is crushed and pressed to squeeze the oil out. Olive oil is obtained this way. Sometimes the oil is more difficult to extract and has to be dissolved in a solvent. Once the oil is dissolved, the solvent is removed by distillation, and impurities such as water are also removed, to leave pure vegetable oil. Sunflower oil is obtained in this way.

Structure of vegetable oils

Molecules of vegetable oils consist of glycerol and fatty acids. In the diagram below you can see how three long chains of carbon atoms are attached to a glycerol molecule to make one molecule of vegetable oil.

the molecule has three fatty acid chains joined to one glycerol molecule

The structure of a vegetable oil molecule

You do not need to know any details about the structure of vegetable oil molecules for the exam.

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