Gluten is a complex of structural proteins naturally found in certain cereal grains, typically referring to the combination of gliadin and glutelin proteins.
Grains containing gluten include all species of wheat, barley, rye, and some cultivars of oat; moreover, cross hybrids of any of these cereal grains also contain gluten, e.g. triticale. Gluten makes up 75–85% of total protein in bread wheat and it is a key compund in bakery and related technological processes in food industry.