Wheat Gluten. 

Bob's Red Mill Vital Wheat Gluten is the natural protein found in wheat. It contains 75% protein. A small amount added to yeast bread recipes improves the texture and elasticity of the dough. This is often used by commercial bakeries to produce light textured breads, and can easily put the home bread baker on a par with the professionals. Vital Wheat Gluten can also be used to make a meat substitute known as seitan.