Molecular features of wheat doughs enriched with perennial wheatgrass (Thinopyrum intermedium) flour

Thinopyrum intermedium – commonly known as intermediate wheatgrass (IWG) – is a perennial crop characterized by many desirable agronomic traits, such as high biomass yield, and drought and frost resistance. Moreover, the high fiber and protein contents increases the interest in using IWG for human consumption. The aim of this study was to investigate the protein structural features in IWGonly and IWG/wheat systems. IWG based doughs were prepared at ≥50% IWG enrichment in order to produce systems with a total fiber content higher than 10%. IWG-enrichment resulted in faster gluten aggregation and lower peak torque compared to hard wheat flour (as measured by Glutopeak test), suggesting a weakening of the gluten network. Proteins in IWG-doughs had higher solubility and thiol content - as function of IWG content - suggesting that protein network was mostly based on non-covalent interactions. Finally, IWG-enrichment enhanced the non-sheet/sheet ratio, by increasing the unordered structures at the expenses of β-sheet structures but without affecting β-turn structures. The overall results suggest that a 50% IWG-enrichment represents a good compromise between nutritional improvement and maintenance of the protein structural characteristics in dough.