Lecithin

Lecithin a fatlike substance found in the membranes of cells, and particularly abundant in egg yolk. Its scientific name is phosphatidyl choline. Lecithin is a powerful emulsifier (see emulsion), a fact exploited in the making of mayonnaise and other sauces containing egg yolk. In the food industry lecithin, usually extracted from soya beans, is widely used as a general purpose emulsifier.