ABSTRACT

This chapter discusses the physicochemical properties of the major proteins of egg white and yolk, namely, ovalbumin, ovotransferrin, lysozyme, ovomucoid, ovomucin, and immunoglobulin Y. It presents an overview of the structure-functional relationships of these proteins as food ingredients and some biological functions. Ovalbumin is the predominant protein in egg white, and it constitutes about half of the egg white proteins by weight. It can be easily purified in large quantities by crystallization from ammonium sulfate solution of egg white. A more convenient method to detect the denaturation of ovalbumin is isoelectric precipitation at pH 4.7 in the presence of 0.1 M sodium acetate and 0.5 M NaCl. When eggs are cooked, egg proteins undergo denaturation, coagulation, and gelation. Egg white is an important foaming ingredient for food applications. The foaming properties of proteins are evaluated by their foamability and foam stabilities.