Emulsions 1 of 10 Boardworks Ltd 2011 Emulsions

Emulsions 1 of 10 © Boardworks Ltd 2011

Emulsions Learning Objectives: 1. Explain how the properties of emulsions make them suitable for their uses. 2. Explain how emulsifiers work.

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What is an emulsion? • emulsion = a mixture of two liquids which normally cannot be combined, such as oil and water.

What is an emulsion? Fine droplets of one of the liquids are dispersed through the other. Over time, emulsions will separate into layers. However, if an emulsifier is added to the liquids, they will not separate. 5 of 10 © Boardworks Ltd 2011

Examples of emulsions fat • • • milk mayonnaise ice cream salad dressings skin creams paint 6 of 10 water MILK © Boardworks Ltd 2011

Properties of emulsions Emulsions are thicker than oil or water and have special properties, which make them very useful in several ways. Mayonnaise is an emulsion with a thick, creamy texture, which is pleasant with food. It is made with egg yolks, which contain the natural emulsifier lecithin (E 322). Emulsifiers are used in cosmetics and paints to give a good appearance and increase the coating ability of the products. 7 of 10 © Boardworks Ltd 2011

• Emulsifiers keep the two substances in an emulsion from separating. • Contain two parts with different properties • Hydrophilic end = “water loving”, interacts with water molecules • Hydrophobic end = “water fearing”, interacts with oil molecules