Food emulsifiers are chemical substances that help food ingredients, such as water and oil, to blend when mixing, forming an emulsion. Emulsifiers are also used as aerating agents to make desserts such as mousses and cakes -- and as crystallisation inhibitors, to avoid the formation of white patches on chocolates. Common emulsifiers include lecithin, mono and diglycerides, glycerides, monoglyceride derivatives, and fatty acid derivatives.