Impact of oligomeric procyanidins on wheat gluten microstructure and physicochemical properties.

We found that oligomeric procyanidins improve the physicochemical properties of wheat flour, and that a more compact and denser gluten microstructure is formed when an increasing amount of oligomeric procyanidins is incorporated. Further, we found that oligomeric procyanidins alter the rheological properties, molecular weight distribution, secondary structure, and thermal stability of gluten, and that oligomeric procyanidins alleviate the loss of extensibility and viscosity after the dough is exposed to high temperatures. Collectively, these results imply that oligomeric procyanidins improve the rheological properties of flour-based foods, likely by (1) regulating sulfhydryl/disulfide redox reactions in the gluten network and impairing the formation of large polymers, and by (2) binding to hydrophobic sites in gluten proteins and altering their conformation.