Yolk
An egg yolk is the part of an egg which serves as the food source for the developing embryo inside. The yolk together with the germinal disc is a single cell. The egg yolk is suspended in the egg white (known more formally as albumen or ovalbumin) by one or two spiral bands of tissue called the chalaza.
As a food, yolks are a major source of vitamins and minerals. They contain all of the egg's fat and cholesterol, and almost half of the protein.
Uses
- It is sometimes separated from the egg white and used in cooking (for mayonnaise, custard, hollandaise sauce, crème brûlée, avgolemono, and ovos-moles)
- It is used in painting as a component of tempera
Composition of chicken egg yolk
The yolk makes up about 33% of the liquid weight of the egg; it contains approximately 60 calories, four times the caloric content of the egg white.
All of the fat soluble vitamins, (A, D, E and K) are found in the egg yolk. Egg yolks are one of the few foods naturally containing vitamin D. Egg yolk is a source of lecithin, an emulsifier.
A large yolk contains more than two-thirds of the recommended daily limit of 300mg of cholesterol.
External links
- Eggs from the Agricultural Marketing Service of the U.S. Department of Agriculture
- Anatomy of an Egg from the Exploratorium
- Making egg tempera from The Society of Tempera Painters