Physico-Chemical Properties of Flour, Starch, and Modified Starch of Two Rice Varieties

The physical and chemical properties of the flours, starches, and modified starches of indics rice and japonica rice were investigated in this paper. Results showed that the swelling powers of flour, starch, and phosphate starch [substitution degree (DS)=0.065] of japonica rice were significantly higher than those (DS=0.065) of indics rice. The transmittance of modified starches was highest; and that of flours was lowest. The pasting property investigated with rapid visco analyzer (RVA) indicated that the peak viscosity and breakdown value of paste with high swelling power were high. Furthermore, the effect of protein and amylose content on pasting property were investigated. The results of rheological properties determined using rheological rheometer showed that at the same temperature, the storage modulus (G') of flour, starch, and modified starch of indica rice was higher than that of japonica rice. For each variety, the G' of flour was the highest, while the G' of modified starch was the lowest.