Physicochemical properties and correlation analysis of retrograded starch from different varieties of sorghum

Summary Sorghum germplasm resources were abundant, and their comprehensive utilisation was also more in‐depth. Starch had attracted much attention as the main component in grain, but starch retrogradation limited its better development and utilisation. Therefore, the property changes of sorghum starch retrogradation were studied. The differences in the properties of the four kinds of sorghum starches during retrogradation were mainly due to composition and structure among the varieties. With the increase in retrogradation days, the order of L1 starch was better at 0.994, the retrogradation rate of L13 starch increased by 36.23%, and the recrystallisation degree of H5 starch was 0.064 worse than that of native starch. However, the physicochemical properties of H1 retrograded starch were different from those of the other three. It was shown that the solubility increased to 47.67%, the transparency was 43.36%, and the water‐holding capacity was 91.35%. Retrogradation made that the surface of sorghum starch gel fragments had an orderly scale‐like structure, which did not cause the generation of new groups, reduced the crystalline strength and the energy required for gelatinisation. The crystallisation rate was positively correlated with syneresis, swelling and orderliness, as well as T 0 , T p , T c and Δ H , and negatively correlated with water‐holding capacity.