Bread dough needs to be elastic in order to capture
the gases created by the yeast, stretch as bubbles form in the dough,
expand, and rise. Without that elasticity, bread would not have the
open texture we enjoy nor would bread be chewy. But what creates that
elasticity?
The endosperm of the wheat contains two important
proteins, glutenin and gliadin. When wheat flour is mixed with water,
these two proteins link with the water molecules and crosslink with
each other as they are physically manipulated by kneading. It takes a
certain amount of physical manipulation to bring these molecules into
contact and create strong links. As the kneading continues and these
molecules create stronger bonds, gluten is formed. It is gluten that
gives the dough elasticity.
If you watch the dough being mixed with the bread
hook in your stationary mixer, you will see changes occur in the dough
as the kneading takes place.