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 ΔH, and negatively correlated with water-holding capacity.

(1) Background: In this study, aiming at the problems of low efficiency and high energy consumption in the esterification reaction of OSA and starch, the jet milling technology was used to pretreat corn starch and starch raw materials with different pulverization strengths were obtained by controlling the speed of the classifier. (2) Methods: The starch obtained under different classification speeds was modified by esterification with OSA. Using CLSM, FTIR, XRD, NMR, FTIR, XPS, and other technologies, the modification effect was verified, and the physical and chemical properties of J-OSA-Starch such as DSC, RVA, transparency, and emulsifying properties were determined. (3) Results: Jet milling pretreatment significantly reduced the particle size of corn starch and improved the reaction efficiency and degree of substitution during esterification with OSA. After pretreatment, the corn starch granules were broken, and the relative crystallinity was significantly reduced. CLSM, FTIR, XPS, and NMR confirmed the esterification of corn starch with OSA, which increased with increasing crushing strength. The thermodynamic properties and viscosity of J-OSA-starch decreased with the increase in the classification speed. Jet milling pretreatment enhanced the clarity, emulsifying activity, and emulsifying stability of OSA-modified corn starch. (4) Conclusions: Jet milling pretreatment can effectively increase the esterification efficiency of starch and OSA. Therefore, jet milling can be used as a pretreatment to improve the esterification of starch OSA and produce modified starch for industrial applications.

Summary Starch is the major nutrient fraction in mung beans, wherein any physicochemical change in them while in germination as pre‐processing tactics influences their properties and hence application broadness. This study aimed to investigate the effect of ultrasonic synergistic exogenous GABA (γ‐aminobutyric acid) treatment on to the physicochemical and functional properties of mung bean starch during germination. At 96 h of germination, the total starch content was decreased to 21.18% and the amylose and resistant starch contents were 48.29% and 64.39% respectively. The particle size, colour, and water‐holding capacity of germinated mung bean starch were reduced significantly. As the increase in germination time continued, solubility, swelling and transparency increased and then decreased. The estimation of glycaemic index shows a minimum value of 22.52 at 12 h of germination. Combined treatment germination decreased the total starch content and increased the amylose and resistant starch content. The physicochemical properties of mung bean starch were significantly altered. Germination by ultrasound and exogenous GABA (γ‐aminobutyric acid) treatment modifies the functional properties of mung bean starch and provides a theoretical basis for its application in food.

Microwave radiation processing technology is an emerging technology with good penetration, uniform heating, and rapidity characteristics. After microwave wet heat treatment, the viscosity of starch decreased, and the gelatinization temperature changed the granule morphology, crystalline properties, and chemical structure of starch, resulting in changes in the physical and chemical properties of starch. It can effectively improve the sensory quality of food and prolong the shelf life of starch products. It is widely used in food, pharmaceutical, agriculture, and other industries. The pre‐gelatinized starch showed irregular shape, rough surface, and apparent edges and corners. Moreover, the starch particles' crystal structure is destroyed, crystallinity decreased to 11.43%–14.91%, and no new groups are formed. The starch granules changed from an ordered structure to a disordered structure, and the order degree decreased to 0.998–1.025. The enthalpy decreased to 2.22–4.32 J/g, the gelatinization temperature increased to 88.53–94.43 °, and the viscosity decreased significantly. After pre‐gelatinization, the amylose content decreased to 13.84%–16.25%. At 90 °, the solubility and swelling degree decreased to 2.48%–7.33% and 16.80%–17.81%, respectively. The freeze‐thaw water precipitation rate increased to 41.92%–59.35%, the water‐holding capacity increased by 3 times and transparency increased to 93.60%–95.84%.

In this study, four kinds of sorghum starch gels containing different amylose were taken as the research objects and stored for 28 days. The parameter changes of gel properties during the retrogradation of different varieties of sorghum starches were observed using X-ray diffraction, Low-field nuclear magnetic resonance, textural, rheological and anti-enzymatic hydrolysis capacity studies to construct kinetic models for the retrogradation. The results showed that the degree of retrogradation, crystallinity and antienzymatic hydrolysis capacity of sorghum starch increased with the prolongation of storage time, and the crystal forms of H5 (Hongnuo No. 5 sorghum) and L13 (Longza No.13 sorghum) starch changed from type A to B. Among the four kinds of starch, L13 starch had the highest degree of retrogradation, and H5 starch had the strongest recrystallisation ability. The hardness of L13 retrograded starch gel grew fastest with increasing storage time, while the viscoelasticity of H1 (Hongnuo No.1 sorghum) retrograded starch showed a stable trend. Low-field nuclear magnetic resonance was used to detect that the L1 (Longmiliang No.1 sorghum) retrograded starch gel had more free water. The crystallisation rate was positively correlated with hardness, resistant starch content and crystallinity and negatively correlated with springiness, gumminess and resilience.