Gluten (from Latin
gluten "
glue") is a protein composite that appears in foods processed from
wheat and related species, including
barley and
rye. It gives
elasticity to
dough, helping it to
rise and to keep its shape, and often giving the final product a
chewy texture.
As cases of known
gluten sensitivity increase, many foods in the western world are now labeled to clarify whether they contain gluten.
Gluten is the composite of a
prolamin and a
glutelin, which exist, conjoined with
starch, in the
endosperm of various
grass-related grains.
Gliadin, a water-soluble, and
glutenin, a water-insoluble, (the prolamin and glutelin from wheat) compose about 80% of the protein contained in wheat
seed. Being
insoluble in water, they can be purified by washing away the associated starch. Worldwide, gluten is a source of protein, both in
foods prepared directly from sources containing it, and as an
additive to
foods otherwise low in protein.
The seeds of most
flowering plants have endosperms with stored protein to nourish
embryonic plants during
germination. True gluten, with gliadin and glutenin, is limited to certain members of the
grass family. The stored proteins of
maize and
rice are sometimes called glutens, but their proteins differ from wheat gluten by lacking gliadin.