What exactly is gluten

Gluten (from Latin gluten, "glue") is a composite of storage proteins termed prolamins and glutelins and stored together with starch in the endosperm (which nourishes the embryonic plant during germination) of various cereal (grass) grains. It is found in wheat, barley, rye, oats, related species and hybrids (such as spelt, khorasan, emmer, einkorn, triticale, kamut, etc.) and products of these (such as malt). Glutens, and most especially the Triticeae glutens, are appreciated for their viscoelastic properties. Gluten gives elasticity to dough, helping it rise and keep its shape and often gives the final product a chewy texture.

Wheat prolamins are called gliadins, barley prolamins are hordeins, rye prolamins are secalins and oats prolamins are avenins, which are collectively named gluten. Wheat glutelins are called glutenin. In a small part of the general human population, gluten can trigger coeliac disease, non-coeliac gluten sensitivity, gluten ataxia and dermatitis herpetiformis. The occurrence of oat avenin toxicity in people with gluten-related disorders depends on the oat cultivar consumed, because the immunoreactivities of toxic prolamins are different among oat varieties. Also, many oat products are cross-contaminated with other gluten-containing cereals.

True gluten is limited to the grains listed above. The stored proteins of maize and rice are sometimes called glutens, but their proteins differ from true gluten.