Abstract:In order to explore the differences in molecular structure and characteristics of rice starch from different varieties of rice in Ningxia, the starch was extracted using the alkaline method. The crystal structure, crystallinity, molecular order, and gelatinization properties of rice starch from 21 different varieties in Ningxia were detected and analyzed through X-ray diffractometer (XRD), rapid viscosity analyzer (RVA), and Fourier transform infrared spectrometer (FTIR). The results showed that all rice starch molecules had an A-type structure. Different varieties of rice exhibited variations in crystallinity and molecular order, with ‘Ninggeng 28’ having the highest crystallinity at 32.96%. ‘Rice 3’ displayed characteristic absorption peaks at 1 748 cm-1 and 2 852 cm-1 in the infrared spectrum. All RVA curves of rice starch exhibited the trend of increase initialy, followed by a decrease, and increase later. Among them, ‘Ninggeng 41’ had the higher viscosity but poor thermal stability and shear resistance, while‘843’ had low viscosity and ‘Tianjiangyou 169’ showed good thermal stability and shear resistance. The varieties 'Ninggeng 41', 'Daohuaxiang 4', and 'Ningxiang' demonstrated elevated levels of retrogradation. The results could provide a theoretical basis for the classification and fine processing of different rice varieties in Ningxia.
