Effect of Sucrose Addition on Rheological and Thermal Properties of Rice Starch–Gum Mixtures

The effect of sucrose at different concentrations (0, 10, 20, and 30% w/w) on rheological and thermal properties of 5% (w/w) rice starch (RS) pastes mixed with guar gum (GG) and xanthan gum (XG) was examined. The flow behavior index (n) values of RS–gum mixtures in the presence of sucrose were higher than those of the control (0% sucrose), whereas their K and σₒc values were lower. The RS–XG–sucrose mixtures showed much higher dynamic moduli values than the control, while the RS–GG–sucrose mixtures, except for the 30% sucrose concentration, showed lower values, indicating that the viscoelastic properties of RS–XG mixtures were greatly affected by the addition of sucrose. In general, differential scanning calorimetry studies showed that the presence of sucrose resulted in an increase in the gelatinization temperatures and a decrease in gelatinization enthalpy. These results could facilitate the development of RS-based products with improved thermal and rheological properties.