How Sugar is used in Bakery Application?
In bakery applications, sugars are used to impart flavor, aroma and color. During the mixing process, excess gluten development can make doughs and batters rigid and tough. Addition of sugar will ensure that gluten maintains an optimal elasticity, allowing the dough to expand and rise properly. During mixing, flour protein is surrounded with water, forming gluten strands. The strands have thousands of balloon-like pockets that trap gases produced during leavening. These gluten strands are highly elastic, and allow the batter to stretch as the gases expand. Sugars compete for water with gluten proteins, inhibiting their development and allowing proper volume and tender texture.
Sugars allow the dough to rise at an optimal rate during leavening. The naturally occurring irregular surface texture of the sugar crystals encourages yeast growth and effectiveness by providing an immediate and easily accessible source of nourishment. Under appropriate conditions, the yeast cells break down the sugar crystals, releasing carbon dioxide that causes the dough to rise. Addition of shorteners to the dough allows the air to get trapped in the naturally irregular sugar crystals. As the shortening and sugar are creamed together, the trapped air cells get interspersed in the mixture. During baking, these air cells expand with carbon dioxide and other gases from the leavening agents to ensure just the right volume. The sugars naturally interact with proteins from the beaten eggs to stabilize the foam structure. This makes the egg foam more elastic, allowing it to expand as it takes up gases from the leavening process. In bakery products, sugar is recrystallized as water is removed during baking, resulting in a crisp texture. This crispness is increased by the effects of browning (Maillard reaction), which takes place when reducing sugars and nitrogen-containing ingredients (e.g. protein) are heated together. You will read about browning later in this section under the appearance function.
Sugars also act to tenderize bakery products by slowing the rate at which starch molecules become interlinked and proteins break down. Glucose, fructose, sucrose and maltose are used in bread making to increase dough yield and prevent excessive stickiness. While baking un-shortened cakes along with sugars help ensure the cakes "set" correctly. As the temperature rises, egg proteins coagulate, or form bonds among each other. Once egg proteins coagulate, the cake "sets," forming its solid, mesh-like structure. Sugars disperse among the egg proteins and naturally interfere with the bond formations, raising the temperature at which they form. The heat of baking causes the starch in flour to swell from moisture absorption and set in gelatinization. To create a fine, uniformly-grained cake with a soft, smooth crumb texture, the "setting" must be delayed until the optimal amounts of gases are produced by the leavening agents. Sugars are hygroscopic and act to slow the gelatinization process by competing with starch for moisture. This maintains the viscosity of the batter until the optimal amount of gases are produced by the leavening agents, ensuring good texture and volume. Surface cracking is desirable in most cookies. As sugars re-crystallize, it gives off heat that evaporates the water absorbed during mixing. This combines with leavening gases to expand and cause surface cracking of the dry surface.