Chemistry: Plant oils and their uses

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Vegetable oils, emulsions and hydrogenation

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

Vegetable oils are found naturally in seeds, nuts and some fruit and can be extracted by being crushed and pressed to squeeze the oil out. 

Sometimes the oil is harder to extract and has to be dissolved in a solvent. Once the oil is dissolved, the solvent is removed by distillation and the impurities such as water are also removed to leave pure vegetable oil.

Molecules of vegetable oils consist of glycerol and fatty acids.

Vegetable oils have higher boiling points than water so foods can be cooked or fried at a higher temperature than they can be boiled or cooked in water. Foods cooked in vegetable oils cook faster than if they were boiled and have different flavours than if they were boiled. 

Vegetable oils are a source of energy in the diet so food cooked in vegetable oil releases more energy than food cooked in…

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