Effects of sucrose on pasting, thermal, rheological and textural properties of native and alcohol-alkali-treated waxy rice starch.

In this work, the physicochemical properties of native waxy rice starch (WRS) and alcohol-alkali-treated waxy rice starch (AAT-WRS) were studied in the presence of sucrose. The results indicated that the addition of sucrose improved the transparency and freeze-thaw stability of WRS pastes and AAT-WRS pastes. Differential scanning calorimetry showed that the gelatinization temperatures of WRS increased with increased sucrose concentration, but the gelatinization enthalpy increased at low concentration of sucrose and decreased at high concentration. Rheological measurements indicated that sucrose addition had no significant effect on the pseudoplastic shear-thinning behaviors of WRS pastes and AAT-WRS pastes, but changed the apparent viscosity. Dynamic moduli (G' and G″) values of WRS pastes and AAT-WRS pastes with or without sucrose showed frequency dependency and sucrose addition dependency. The elastic behavior was dominant over viscous in the WRS-sucrose mixed pastes, while the AAT-WRS-sucrose mixed pastes was the opposite. The textural paraments of WRS and AAT-WRS before or after retrogradation increased with the increasing concentration of sucrose. These results suggested that sucrose potentially changed the physicochemical properties of WRS and AAT-WRS.