The Whole Story

• A whole egg is composed of a bright yellow yolk surrounded by a clear but slightly opaque white, or albumen. All enclosed in a brown or white shell, the yolk contains significant amounts of several nutrients, including protein, while the white is composed mostly of water and less protein. Together, the yolk and white add stability to baked goods by helping to bind dry ingredients together. When exposed to heat, eggs become firm, a property that solidifies batter for cakes and other baked goods, and beaten eggs act as a leavener that aerates batters, causing them to rise. This property also helps thicken sauces, casseroles and pie fillings.

Y Is for Yellow

• Chef Sarah Moulton states that, not only do egg yolks add richness and flavor to cake batter, they also affect the color. Recipes such as gold cake, for example, rely on the yolks' rich yellow color to turn what would otherwise be a pale off-white batter to one that reflects its name. You can also brush whole eggs or just the yolks blended with a bit of water onto pie crust or bread dough before baking to give them a shiny golden sheen.

One-Role Wonder

• Egg whites contain albumin and ovalbumin, two proteins that help the whites puff up during beating. Albumin creates the characteristic bubbles that appear during whipping, while the ovalbumin stabilizes cake batter during baking. Egg white foam is used most often to make meringues for pies, as in lemon meringue pie; in cheese soufflés and omelets; and in sponge and angel food cakes where the foam acts as a leavener causing the batter to rise.

Considerations

• In addition to their ability to bind the dry ingredients together in batter and dough, eggs also add liquid to the mix. According to Baking911, all baking ingredients are said to either strengthen or weaken a mixture. Like flour, water and milk, whole eggs and egg whites toughen dough or batter, while egg yolks have the same tenderizing ability as do fat and sugar. The aim in baking is to achieve a balance among the ingredients, and most recipes have been worked out to produce the desired results.