Rheological and thermal properties of blend systems of rice flour and potato starch

The rheological and thermal properties of blends of rice flour (RF) with potato starch (PS) at different RF/PS ratios (9/1, 8/2, 7/3, 6/4, and 5/5) were examined. Steady and dynamic shear rheological tests indicated that the consistency index, yield stress, and dynamic moduli (G′ and G″) values of the RF-PS blends increased with an increase in the mixing ratio of PS. All blend samples exhibited high shear-thinning fluid characteristics. Tan δ values of all the blends were lower than those of RF and PS, showing that the presence of PS increased the elastic property of RF. DSC studies showed that the transition temperatures and enthalpies of gelatinization of the blends appeared to be greatly influenced by the addition of PS. In general, these results suggest that the presence of PS in RF modified the rheological and thermal properties, and that these modifications were dependent on the mixing ratio of PS.