Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grains that have been proven capable of triggering celiac disease. These include any species of wheat (such as common wheat, durum, spelt, khorasan, emmer and einkorn), barley, rye and some oat cultivars, as well as any cross hybrids of these grains (such as triticale). Gluten makes up 75–85% of the total protein in bread wheat.
Glutens, especially Triticeae glutens, have unique viscoelastic and adhesive properties, which give dough its elasticity, helping it rise and keep its shape and often leaving the final product with a chewy texture. These properties, and its relatively low cost, make gluten valuable to both food and non-food industries.
Wheat gluten is composed of mainly