Effects of konjac glucomannan on heat-induced changes of wheat gluten structure

Effects of konjac glucomannan on the structure of wheat gluten were investigated at variable temperatures in this study. Dynamic oscillatory rheology study showed that konjac glucomannan conferred stiffness on gluten with a higher tan delta data at 25 degrees C and 55 degrees C, but this parameter was lower at 75 degrees C and 95 degrees C. Konjac glucomannan decreased the content of thiol equivalent groups and increased the alpha-helix/beta-sheet content ratio, respectively. The thicker layer of gluten protein with 5% konjac glucomannan was observed by scanning electron microscopy. This study revealed that konjac glucomannan could alter the conformations of gluten proteins upon heating via non-covalent interactions and physical entanglements. It is likely that konjac glucomannan promotes protein aggregation by strengthening hydrophobic interaction at 25 degrees C and 55 degrees C, and alleviates heat-induced denaturation by decreasing the flexibility of polypeptide chain at higher 75 degrees C and 95 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.