What is the natural emulsifier found in eggs?

The natural emulsifier found in eggs is lecithin, a phospholipid that plays a crucial role in the culinary world, particularly in emulsification processes. Emulsification involves mixing two immiscible liquids, like oil and water, to form a stable blend, and lecithin assists by reducing the surface tension between these liquids.

In eggs, lecithin is primarily located in the yolk, which is why egg yolks are commonly used in recipes for emulsified sauces such as mayonnaise and hollandaise. This natural emulsifying property enables the formation of a smooth and uniform product, enhancing both texture and flavor.

The other options listed do not possess emulsifying qualities to the same extent. Casein is a protein found in milk, albumin is a protein in egg whites, and keratin is a structural protein found in hair and nails, none of which serve the function of emulsifying agents like lecithin does within culinary applications.