Preparation and physicochemical properties of OSA modified Cyperus esculentus starch nanoparticles

The aim of this study was to investigate the Octenyl succinic anhydride (OSA) modification and nanonization of Cyperus esculentus starch (CES) on its physicochemical properties. Cyperus esculentus starch nanoparticles (SNPs) were prepared by nanoprecipitation method and modified with OSA. The results showed that the average particle size of the prepared SNPs was 125.25 nm, and the OSA modified nanoparticles (OS-SNPs) were between 411.16 and 442.07 nm. Chemical group analysis indicated the successful esterification reaction of OSA. Crystallographic structure analysis showed that the crystalline type of CES remained unchanged after OSA modification, but the crystallinity was slightly decreased. Moreover, SNPs exhibited a V-type diffraction peak. Morphological observation results showed that the hydrophobic groups introduced after OSA modification of SNPs had caused particle deformation and formed a network structure. In addition, the gelatinization temperature of starch decreased after OSA modification, and the gelatinization temperature could no longer be measured after nanonization. The OSA modified CES (OS-CES) had shown higher viscosity, swelling power and solubility during the gelatinization process. While the nanonized samples had no obvious viscosity change during the heating process, the solubility remained at a relatively high level of 70-90 %.