Sweet Bread Dough Issues

• Whether yeast-raised or leavened with baking soda or baking powder, sweet bread doughs involve a delicate balance between gluten-rich flour and tenderizing fats and sugars. Basic bread results from the formation of gluten strands when flour is mixed with liquid. Adding fats to that mixture shortens the strands, making dough less elastic; this action is described in the terms shortening, shortbread and shortcake. Shorter gluten strands produce flaky or crumbly dough. This lightness can be enhanced by adding sugar, whose granules facilitate the incorporation of air into creamed or beaten shortening. Large quantities of sugar and fat in proportion to flour yield the texture that distinguishes cake from bread. Adding eggs to sweet bread dough can make short dough more elastic, when fat and sugar have made it less so. Egg yolks alone, however, cannot perform that function.

Egg Yolk Properties

• The yolk contains approximately one half of the protein and all of the fat, including all the cholesterol, in an egg. In cooking, egg yolk acts as an emulsifier, blending with milk fats and proteins to create a custard, for example. In baking, the fat in egg yolk helps to hold fat particles in combination with carbohydrate particles, preventing fat separation from the dough. This helps keep dough moist and tender.

Egg White Properties

• Egg white, or albumen, contains protein and liquid, contributing to the elasticity and expansiveness of dough. Two proteins, albumin and ovalbumin, combine to produce foam, a network containing tiny air bubbles. This network coagulates in the presence of heat, trapping bubbles and making dough light. Egg white contributes moisture that combines with carbohydrates, a sticky trap for air bubbles formed by leavening agents and a drying accelerant that helps form the outer crust during baking.

Whole Eggs vs. Egg Yolks

• Adding egg yolks alone to a dough can prevent fat separation and increase moisture, but yolks will not increase elasticity. Substituting yolks for all the eggs specified in the recipe will yield crumbly, damp results. Whites alone make dough more cohesive, lowering fat and cholesterol content, but at the cost of richness. Whole eggs function best in the tensions between flour, fat and sugar that make sweet breads so delightful and tasty.