Abstract: This investigation studied the effects of konjac glucomannan (KGM) on the molecular mass, free sulfhydryl content, secondary structure, microstructure and functional properties (water-binding capacity, rheological properties and thermal properties) of gluten from frozen wheat dough. SDS-PAGE, a rheometer, a differential scanning calorimeter, an ultraviolet (UV) spectrophotometer, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM) were used to analyze the structural and functional properties. The results showed that added KGM significantly enhanced the water-binding capacity and improved the viscoelasticity, the denaturation temperature (Tp) and denaturation enthalpy (ΔH) of gluten. In the presence of KGM, the contents of gluten α-helix and β-sheet increased, but the contents of β-turn and random coil decreased, improving the freeze stability of gluten. SEM image analysis showed that the microstructure of gluten added with 1.5% KGM had a distinct spongy structure with larger pores. KGM has a significant effect on gluten in frozen wheat dough and can act as a cryoprotectant for gluten.

Key words: konjac glucomannan, gluten, structure, water-binding capacity, rheological properties, thermal properties