Gluten

Gluten is a complex mixture of storage proteins found in wheat grain. Its two major protein groups are gliadins and glutenins, each of which contains many related proteins. These proteins are particularly rich in the amino acids glutamine and proline. When wheat flour is mixed with water, gluten proteins interact to form a network that gives dough many of its characteristic physical properties .^1,2

Gliadins are largely monomeric proteins and contribute particularly to the viscosity and extensibility of dough. Glutenins form larger protein polymers linked partly by disulfide bonds and contribute more strongly to elasticity and strength. Together, these properties allow wheat dough to stretch while retaining its structure, which is important in products such as bread .^1,2

Strictly speaking, gluten refers to the characteristic protein complex of wheat. In clinical and nutritional usage, however, the term is often used more broadly to include closely related cereal storage proteins that can provoke reactions in people with celiac disease. These include secalins in rye and hordeins in barley. Oat avenins are also related storage proteins, although their immunological behavior differs from that of wheat, rye, and barley proteins .¹

Gluten is therefore not a carbohydrate or a single protein. It is a heterogeneous mixture of cereal storage proteins, with gliadins and glutenins forming the principal components of wheat gluten .^1,2