These foods do not contain wheat, rye, triticale, or barley flours. The main protein complex in wheat is gluten and small fractions of this complex – gliadins – cause and adverse reaction in sensitive people. Rye also contains some gluten, and there are similar protein fractions in barley (hordein) and oats (avenin).
Some cereals – rice, maize, sorghum, and millets – are naturally free of the harmful proteins, since neither they nor the pseudo-cereals – buckwheat, quinoa, and amaranth – contain any gluten. Mixtures of these grains, sometimes with other ingredients such as potato flour, are used to produce gluten-free flours that can then be made into breads, cakes, and biscuits. Ready-made bread, cakes, and biscuits are also available, as are bread mixers. Bread made from gluten-free flours is not the same as ordinary bread, because the fermentation of gluten is responsible for the elasticity of the dough and hence the structures of the loaf. Most gluten-free bread is made from wheat starch, which is flour from which the gluten has been removed plus additives to enable the bread to rise. Milk or other proteins may be added to the flours to improve the texture and color of the baked products, and these foods should therefore not be regarded as low-protein products.
Traces of gluten may remain in wheat starch, and some people are intolerant to even small amounts. (The World Health Organization’s Codex Alimentarius defines a product as being gluten free if the nitrogen content does not exceed 0.05 g per 100 g flour).