Comparative investigations of gluten proteins from different wheat speciesI. Qualitative and quantitative composition of gluten protein types

In contrast to the hexaploid common (bread) wheat, little information is av ailable on the qualitative and quantitative compositions of gluten proteins from other cultivated wheat species. Therefore, representatives of hexaplo id spelt. tetraploid durum wheat and emmer, and diploid einkorn were compar ed with three classes of common wheat (winter wheat, spring wheat, wheat ry e hybrid). The flours were extracted to yield total endosperm proteins and the gluten protein fractions (gliadins and glutenin subunits). The extracts were characterised using sodium dodecyl sulfate polyacrylamide gel electro phoresis and reversed-phase HPLC; both methods revealed that gluten protein groups and types known from common wheat (omega-, alpha-, gamma-gliadins, HMW and LMW subunits of glutenin) were present in all species. The HPLC pla tterns of gliadins and glutenin subunits from species with the same genome composition (common wheat/spelt or durum wheat/emmer) were related, and tho se of einkorn quite different. According to the quantities determined by re versed-phase HPLC, alpha-gliadins were predominant in most cases, followed by gamma-gliadins and LMW subunits; omega-gliadins and HMW subunits were ge nerally minor components. Common wheats were characterised by the highest p roportions of total glutenins and HMW subunits- which are known to be impor tant for breadmaking quality. Moreover, the lower ratio of gliadins to glut enins was typical. Emmer had the lowest proportions of total glutenins and of HMW and LMW subunits, together with einkorn the highest proportion of al pha-gliadins, and, by far, the highest ratio of gliadins to glutenins. The values for spelt and durum wheat were mostly in a medium range between comm on wheats, emmer, and einkorn, respectively. Amongst common wheats, spring wheat was characterised by more balanced quantities of alpha- and gamma-gli adins, and wheat rye hybrid by the highest proportions of omega-gliadins.