Abstract: In order to investigate the synergism between konjac gum and xanthan gum during gelation, we prepared 1% mixed gels with different konjac gum to xanthan gum ratios (2:8, 4:6, 5:5, 6:4, and 8:2) by mass. The rheological properties and gelation kinetics of the mixed system were determined, and the underlying mechanisms were explored. The results showed that the konjac gum-xanthan gum system was pseudoplastic. As the proportion of konjac gum increased, the consistency coefficient K increased and the fluid index n decreased. The dynamic viscoelastic properties were also changed with changing ratio between konjac gum and xanthan gum. When the ratio between konjac gum and xanthan gum was 6:4, the strongest pseudoplasticity and elasticity were observed as indicated by the highest K value and lowest n value. The rate of gelation was greatly affected by the ratio between two gums. Slow gelation rate and poor gel strength were found at a ratio smaller than 6:4. When the ratio was increased to 6:4, the gelation process was accelerated; the SDRa and G’ curves rapidly rose and the gel strength was increased. However, the gelation rate was decreased with further increasing konjac gum/xanthan gum ratio. The kinetic data were well fitted to the Arrhenius equation with a determination coefficient greater than 0.98, indicating an excellent goodness of fit. The activation energy for the gelation process was significantly increased at a 6:4 ratio between konjac gum and xanthan gum (P < 0.05) and it differed in the high- and low-temperature ranges.

Key words: konjac gum-xanthan gum, mixed system, rheological properties, gel formation, dynamic analysis