Viscoelastic changes of rice starch suspensions during gelatinization

Abstract

Dynamic rheometry was utilized to characterize viscoelastic changes during heat-induced gelatinization of 2 domestic rice starch suspensions, 1 from waxy and the other from indica rice. Gelatinization included 4 stages: suspension into sol, sol transition to gel, network destruction, and network strengthening. Increase in storage modulus (G') was observed as early as about 47 degrees C. For indica rice, the maximum value (G(max)') was higher, and the decrease afterwards was slower, owing to its higher amylose content. The effects of heating time and temperature were found additive. Sealing samples with oil affected the accuracy of measurement, Finally, the network of starch gels had a larger fractal dimension than that of soy protein isolates previously investigated, suggesting firmer food texture.