Wheat seed, sectioned to reveal endosperm and embryo

Wheat — a prime source of gluten

Gluten /gloot-en/ is a composite of the proteins gliadin and glutenin. These proteins are found in the endosperms of some grass-like grains such as wheat, rye and barley. Gliadin and glutenin make up about 80% of the protein contained in wheat seed. As they are insoluble in water, they can be got by washing away the starch in the grain. Worldwide, gluten is an important source of food protein, both in foods prepared directly from grains with gluten in them, and as an additive to foods that are low in protein.