Physical Changes During Dough Formation

Study Notes

Flour components, primarily starch and protein, are hydrated when they come into contact with water.
There are two main types of starch: native starch, which absorbs water on the outside of the particle, and damaged starch, which absorbs close to its own weight in water.
Both native and damaged starch act as filling agents in a dough system.
The two primary proteins in wheat, glutenin and gliadin, are responsible for dough formation and can absorb 200-250% of their weight in water.
Glutenin affects the elasticity of the dough, while gliadin affects its extensibility.
When glutenin and gliadin proteins absorb water, they inflate and become attracted to each other, forming chains of proteins called gluten.

The mechanical operation of the dough hook works the gluten into an organized structure through two distinct movements: stretching and folding.
This process creates a three-dimensional gluten structure, with longer, finer, and more overlapped chains of gluten.
A longer mix generates a well-developed gluten structure, while a shorter mix generates an underdeveloped one.
Overmixing can break the gluten chains, leading to a weaker gluten structure.

Two main natural chemical reactions occur during mixing: fermentation activity and enzyme activity.
The rate of these reactions depends on the quantity of water used.
Wet dough generates faster fermentation activity, which may require reducing the level of yeast needed in the formula.
Oxidation occurs during mixing, incorporating oxygen into the dough and affecting gluten bonds and pigments.
Too much oxygen can lead to a whiter crumb color and a blander flavor, while some oxygen is necessary for better gluten bonds and tolerance.

Overmixing can lead to too much oxygen incorporation, negatively affecting carotenoid pigments and resulting in a whiter crumb color and a blander flavor.
Salt can be used to slow down chemical reactions, including oxidation, and minimize its negative effects.
Incorporating salt at the beginning of mixing can retard oxidation, while delaying salt incorporation can lead to a whiter crumb structure but at the expense of flavor.