Gluten is a substance made up of the proteins found
in wheat flour that gives bread its structure, strength, and texture.
Without these marvelous little proteins, bread would not be bread. It
also explains why it is so hard to make bread from rice, potato, or
oat flour and why wheat flour has to be added to rye flour to make
bread—only wheat has enough protein. The gluten makes the bread.
Gluten is developed in the dough when the proteins
absorb water and are pulled and stretched in the kneading process. As
the proteins are worked, they become long, flexible strands. As the
yeast produces gases in the dough, mostly carbon dioxide, these
strands trap the gas bubbles and the dough expands. When we put the
bread in the oven, the gluten strands coagulate or solidify much as
the protein in eggs solidifies as the egg cooks.
How is it that we can use flour to make both a
tender cake and firm chewy French bread? The gluten makes the
difference. In a cake, we want little gluten development.