Science of baking

Each ingredient has a task, and once heat is added, a blob of batter transforms into a tasty baked treat. For bread baking, the flour should be a wheat flour which is high in gluten (protein) as this is the substance that gives bread its fine texture and supports the ingredients during rising.

The ingredients have different roles which can be split into three categories. They can be structural agents, leavening agents, or shortening agents.

Flour provides structure. wheat flour contains the proteins glutenin and gliadin. When the flour gets wet from the milk or eggs, two proteins join to form long strands of gluten. Mixing the batter creates even more gluten, which holds everything together. Gluten can stretch and has pockets that can trap air and other molecules, such as starch.

As soon as the yeast has been added to the dough or batter, the yeast begins to feed on the starch in the mixture, forming sugar, alcohol and carbon dioxide. The bubbles of CO2 cause the dough to expand ("rise"). The dough must be "kneaded" thoroughly to distribute the bubbles evenly and then left to rise again.

During the baking the bubbles will expand and the cake/bread will 'rise'. At the same time the stretchy gluten in the flour – which has formed an elastic network round the air bubbles – will stretch until, at a higher temperature, it loses its elasticity and the shape of the cake becomes fixed.
Science of baking