Effects of electron beam irradiation pretreatment on the substitution degree, multiscale structure and physicochemical properties of OSA-esterified rice starch

In order to investigate the effect of electron beam irradiation (EBI) pretreatment on the structure and physicochemical properties of octenyl succinic acid (OSA) esterified rice starch. In this study, rice starch was pretreated with EBI (2, 4, 6 KGy) followed by OSA esterification (3%, 6%). EBI pretreatment significantly increased the OSA-esterified starch's degree of substitution (0.0173-0.0305). However, the relative crystallinity of OSAesterified starch decreased after EBI pretreatment. And the peak viscosity, trough viscosity and final viscosity of starch decreased significantly with the increase in irradiation dose. Moreover, EBI pretreatment significantly reduced gelatinization temperature and B3 chain content of OSA-esterified starch, and significantly increased transparency, solubility, swelling power and A chain content. In addition, OSA-esterified starch's RDS content decreased and RS + SDS content increased after EBI pretreatment. The PCA results suggest that EBI may affect the physicochemical properties of starch by acting on its structure. The results showed that EBI pretreatment improved the physicochemical and functional properties of OSA-esterified starch, which is expected to broaden its application scope.