Abstract:The structure and physicochemical properties of six different varieties of rice starch before and after aging were compared and analyzed. The results showed that the amylose content, volume mean diameter (D[4,3]), crystallinity, gelatinization on set temperature (To), peak temperature (Tp), conclusion/end set temperature (Tc) and gelatinisation enthalpy (ΔH) of different varieties of rice starch were in the ranges of 17.24%~22.69%, 5.74~7.09 μm, 16.45%~18.19%, 64.77~73.03 ℃, 71.73~81.13 ℃, 77.17~87.40 ℃, and 12.62~18.44 J/g, respectively. After aging of rice starch, the amylose content significantly increased (p<0.05), and crystallinity significantly decreased, with the aging having no significant effect on the starch crystal form and short-range order. Aging had significant effects on the gelatinization characteristics of rice starch before and after retrogradation, and the To, Tp, Tc and ΔH values of rice starch decreased significantly after retrogradation. With the increase of temperature, the solubility and swelling degree of rice starch increased significantly. Aging decreased the swelling degree, solubility and light transmittance of rice starch. The amylose content of rice starch was positively correlated with To and To' (To of retrograded starch), D[4,3] of rice starch was positively correlated with To, To' and light transmittance, and the crystallinity of rice starch was positively correlated with To, ΔH and ΔH' (ΔH of retrograded starch). The results of this research can provide a theoretical basis for rational utilization of rice resources in Hubei, and efficient utilization of old/aged rice resources and product development.
