Triticeae Glutens

Triticeae Glutens

Triticeae glutens are seed storage proteins found in mature seeds of grass tribe Triticeae. Seed glutens of non-Triticeae plants have varieties of similar properties, but none singly can perform on a par with those of the Triticeae taxa, particularly the triticum species (bread wheat, durum wheat, etc). By its strictest definition gluten means the factors in bread wheat (Triticeae Triticum aestivum) that give rise to the sticky capacity that allows dough to rise and retain its shape during baking. The same proteins or very similar proteins are also found in other triticeae genera and species. What distinguishes bread wheat from these other grass seeds is the quantity of these proteins and the level of subcomponents, with bread wheat having the highest protein content and a complex mixture of proteins derived from 3 grass species (Aegilops speltoides, Aegilops tauschii strangulata, and triticum monococcum). Because of the sequence similarity of these glutens, gluten sensitivity (most importantly Coeliac disease) has a reactivity primarily restricted to grass seeds of this tribe (known reactivity to Triticum, Secale, Triticosecale, Hordeum, Aegilops, and Agropyron), but this may extend to related grass seeds of Aveneae. Between 2 and 10% of gluten sensitive individuals are also sensitive to oats, but it is not clear how much of this is due to contamination of triticeae seeds in oats or allergic responses (versus intolerance). Therefore when broadly applied the designation of Gluten-free applies to foods bearing the seed storage proteins derived from Triticeae.

Triticeae seed proteins fall into four groups:

• albumins - soluble in hypotonic solutions and are coagulated by heat
• globulins - soluble on 'isotonic' solutions
• prolamins - soluble in aqueous alcohol
• glutelins - are soluble in dilute acids or bases, detergents, chaotropic or reducing agents.

Of these proteins the last two, prolamin (in wheat - gliadin) and glutelin (in wheat - glutenin) form the classically defined gluten components in wheat.

Triticeae glutens are primarily important to a developing definition 'gluten-free' in dietary treatments for gluten sensitivity which are intended to exclude pathogenic proteins from the diet of susceptible individuals (namely coeliac disease). The poisonous motifs appear to be spread widely in Triticeae, but not other taxa, for most coeliacs. However all 4 proteins are involved in wheat allergies, and proteins from non-wheats may not be involved in certain gluten allergies, or in idiopathic sensitivities.