ABSTRACT
This chapter describes the general chemical compositions of hen eggs in the market with some comments about the factors affecting the egg composition. The weight and composition of each structural part of hen eggs are more or less different depending on the species, feeding, age of hens, and so on. The main chemical components of hen egg are 12% lipids, 12% proteins, and the rest is water and small amounts of carbohydrates and minerals. Proteins are distributed in all parts of the egg, but most of them are present in the egg yolk and the egg white amounting to 44% and 50%, respectively. Lipids in eggs include true fats, phosphorus, nitrogen and/or sugar-containing lipids, and sterols. Unlike egg white, egg yolk is a homogeneously emulsified fluid. The major portion of egg yolk exists as lipoproteins which are separated into plasma and granule fractions. The chapter presents the composition and physical properties of egg white proteins and egg yolk proteins.
