Tannins improve dough mixing properties through affecting physicochemical and structural properties of wheat gluten proteins

The quality of wheat flour is largely determined by the properties of gluten proteins. Chemical components that influence gluten proteins are used as flour improvers in the flour industry. In this study, tannins which are natural occurring polyphenols were found to improve dough mixing properties. The effects of tannins on the physicochemical and structural properties of gluten proteins were examined, and the results showed that tannins promoted the non-covalent interactions among gluten proteins, although they induced SH/SS interchange reactions in the dough. The beta-turn and alpha-helix conformations were increased, whereas the beta-sheet confirmation was decreased in dough containing tannins as detected by FTIR. Moreover, the addition of tannins promoted the aggregation of gluten proteins, modified the microstructure of gluten networks, and improved the mixing properties. The positive effects of tannins on dough properties implied the potential of tannins as a new flour improver. (C) 2014 Elsevier Ltd. All rights reserved.