Effect of Annealing on Physicochemical Structure and Properties of Chinese Wild Rice Starch

In this study, Chinese wild rice starch was used as the research object to investigate the effects of annealing (ANN) at different temperatures (30, 40, 50, 60 ℃) on the physicochemical structure and properties of starch. Compared with the control group, as the annealing temperature increased, the starch granules were rearranged under hydrothermal action, leading to gradual aggregation, increased particle size, and a significant decrease (P<0.05) in the degree of swelling and freeze-thaw stability. Additionally, the starch water separation rate of ANN-60 was 27.75% greater than that of the control group. ANN did not change the crystallization type or characteristic peak orientation of starch. The crystallinity and short-range order of ANN-60 starch increased by 6.2% and 0.37% respectively. Moreover, after ANN treatment, the peak viscosity of starch decreased significantly (P<0.05), the gelatinization temperature of ANN-60 starch increased by 5.92 ℃, and the gelatinization enthalpy increased by 0.98 J/g. In addition, after ANN, starch exhibited a more compact structure, and gel hardness and adhesiveness increased. ANN-40 had the most significant effect on the viscoelasticity (tanδ) of starch, and the mechanical properties of the gel improved. Studies have shown that the starch treatment temperature has an important effect on the effect of ANN-modified starch. This study provides a theoretical basis for the industrial application of Chinese wild rice starch.