Effects of ascorbic acid and sodium chloride on protein and dough properties of intermediate wheatgrass (Thinopyrum intermedium) compared to wheat, emmer, and rye

Wheat dough is strengthened by ascorbic acid (AA) and sodium chloride (NaCl) because they promote interactions among gluten proteins. The aim of this study was to investigate if these additives induced molecular changes and affected viscoelastic properties of dough made from the perennial grain intermediate wheatgrass (IWG). Empirical and fundamental rheology, the proportion of large polymeric proteins, and changes related to thiols, including glutathione, were assessed and compared to results from dough made with emmer, wheat, or rye. AA had a strengthening effect on IWG, emmer, and wheat dough, but not on rye. Large polymeric proteins in wheat and IWG dough increased with AA, but the change in IWG dough was of low magnitude. Glutathione concentrations were higher in IWG dough with NaCl compared to dough with 30 ppm AA. Activity of glutathione dehydrogenase, which is involved in the AA improver effect by oxidizing glutathione, was detected in all species. Overall, IWG was affected similarly by AA as wheat and emmer but differed from rye. This indicates that protein networks, and cross-links via disulfide bonds could be of importance in IWG dough, like in wheat dough. However, in contrast to wheat, IWG was weakened by NaCl and it appeared to counteract the effect of AA. These results deepen our understanding of how to best utilize IWG flour.