Gluten is one of three main structure builders in baked goods. The other two are egg proteins and starch. While all three are important, gluten, which forms and develops when flour is mixed with water, is probably the most complex of the three and can be the most difficult to control. In fact, a seemingly small change in a formula or mixing method can have a large effect on gluten development. This is especially true with bread and other yeast doughs, which rely heavily on gluten for unbaked dough structure.