Characterization of sweet corncob polysaccharide-chromium (III) complex and its digestion properties and hypoglycemic effect

Sweet corncobs, an agricultural byproduct, undergo limited processing post-harvest. To enhance the utilization of sweet corncobs and amplify their hypoglycemic activity, polysaccharides (SCP) were extracted, purified, and subsequently modified using trivalent chromium ions, resulting in the formation of SCP-Cr(III) with a weight percentage of Cr(III) at 21.99%. The chemical composition and structure of SCP-Cr(III) were analyzed using various techniques, including SEM-EDS, FT-IR, XPS, XRD, AFM, TG, and HPLC. The findings revealed that the binding mode of SCP-Cr(III) involved the formation of Cr-OH and Cr-O bonds with the glycan chains. The major constituents were glucose, galactose, xylose, and arabinose, with molar ratios of 95.66:1.94:0.43:1.31. Furthermore, it was observed that the fundamental structure of SCP-Cr(III) remained unaltered after simulated digestion. In vitro hypoglycemic experiments demonstrated that SCP-Cr(III) exhibited significant inhibitory effects on alpha-glucosidase and alpha-amylase, with a mixed pattern predominantly driven by competitive inhibition. These findings suggest that SCP-Cr(III) possesses greater hypoglycemic potential compared to SCP alone. Thus, this study provides a theoretical basis for the application of sweet corncob, an agricultural byproduct from processing, in the development of hypoglycemic functional food products.