The differentiation between condensed and hydrolyzable tannins with different molecular weights in affecting the rheological property of wheat flour-based dough

The rheological property of wheat flour-based dough (WFD) has an important influence on its processing characteristics, which is crucial to the end-products. With the aim of improving the rheological property of WFD, this study chose oligomeric proanthocyanidins (OPC) from grape seed and tannin acid (TA) as improvers and investigated their differentiation in affecting the rheological property of WFD. The addition of OPC and TA improved the rheological property of WFD through forming hydrogen bonds and hydrophobic forces with gluten. Tannins at a low concentration promoted the formation of a denser gluten network via forming new bonds with gluten, while high-concentration tannins disrupted the gluten network via breaking the disulfide bonds (S-S) in gluten. This concentration-dependent effect was a result of the competence between the formation of new bonds and the destruction of S-S in gluten. Compared to OPC, TA exerted a stronger influence on the rheological property of WFD, which was mainly due to their huge difference in molecular weight. This study may provide some theoretical guidance for the application of tannins in the wheat-related industry.