Typical Formulas for Three Types of Cakes

Bakery products such as breads are characterized by a typical porous structure and a high specific volume. To obtain such a porous structure, air bubbles have to be incorporated during a mixing or blending step. Gas retention and final volume of the baked good depend, therefore, to a large extent on how fast these bubbles disappear again by one of the following processes: Buoyancy is the process by which bubbles rise to the surface and is driven by a difference in density between the gas and the liquid phase. This process can be described by Stokes law, stating that the velocity by which bubbles rise depends on the difference in density between the gas and the liquid, the viscosity of the liquid phase, and the radius of the bubble. So the larger bubbles rise faster to the surface, especially when the viscosity of a cake batter or dough is low. Disproportionation is the process by which larger bubbles grow while smaller bubbles gradually disappear. This process is driven by the difference in surface pressure (P=2γ/R), which is higher in smaller bubbles than in larger bubbles and which is lower when the surface pressure at the gas water interface is lower (e.g., by adding surfactants). The speed at which the smaller bubbles decrease in size while the larger increase in size is controlled by diffusion, i.e., by how fast the gas in a small bubble can diffuse through the liquid phase into a larger bubble. Because carbon dioxide gas is more soluble in water and is in equilibrium with bicarbonate that is highly soluble in water, carbon dioxide gas bubbles will equilibrate (disproportionate) much faster than air bubbles. Coalescence is the process by which the thin lamella between two adjacent bubbles collapses to form one bigger bubble. Coalescence is the most important process (more important than disproportionation and buoyancy) by which bubbles disappear in porous bakery products such as bread and cakes where gas retention is maximized by stabilizing the lamella between the bubbles. INGREDIENTS RICH WHITE LAYER CAKE ANGEL FOOD CAKE COMMERCIAL POUND CAKE