Which component in egg yolk acts as an emulsifier?

Lecithin is a phospholipid found in egg yolks that functions as an effective emulsifier. Emulsifiers are substances that help stabilize mixtures of two or more immiscible liquids, such as oil and water, creating a homogenous and stable blend. The molecular structure of lecithin allows it to interact with both water and fat, which is essential in creating emulsions found in salad dressings, mayonnaise, and sauces. This property makes egg yolk a vital ingredient in many culinary applications where emulsification is needed.

In contrast, cholesterol is a type of fat that is present in egg yolks but does not have emulsifying properties. Casein and fibroin are proteins found in other foods; casein is primarily in milk, whereas fibroin is a silk protein, neither of which contribute to emulsification in the same way that lecithin does. Thus, the role of lecithin as an emulsifier in egg yolk is what makes it crucial for various food preparations.