Editor’s note: This article is derived from a recent workshop “Aeration in Baked Goods: Using Eggs to Create Foams,” conducted during the National Egg Products School by Shelly McKee, Ph.D. of Auburn University, Ala., in which she showed how bakers can best use eggs to create optimal foams. McKee began with background information that included deeper understanding of the components of the whole egg as well as its main parts, the white and the yolk and their subcomponents.
Eggs undergo a series of physical and chemical changes after leaving the hen. They begin to lose water and become more basic as the pH level rises from 7 to 9, thinning the egg white and weakening the yolk membrane. Storage at room temperature or high temperatures increases the rate of these chemical changes. The changes also negatively influence the quality of the egg proteins and thereby diminish the egg’s functional properties. On a solids basis, egg white is almost entirely protein—the purest and most bioavailable protein of any food source—and practically the sole source of these egg proteins. These include conalbumin, globulins, ovalbumin and ovomucin. It is these proteins that enable egg whites to be whipped into a foam that can reach up to six to eight times greater volume than the unwhipped, liquid egg white. No other natural food ingredient can create as large of a food foam as egg white.