Effects of Nanocellulose on the Physicochemical-Digestive Characteristics of Corn Starch

This study investigated the effects of nanocellulose (NC) on the physicochemical properties, multi-scale structure, and in vitro digestibility of corn starch (CS). The results showed that NC complexed with CS through non-covalent bonds, and the absorbance ratio of 1047 to 1022 cm^-1 increased from 0.38 to 0.72 with increasing NC content. NC-CS complexes exhibited an A + V-type structure with relative crystallinity ranging from 26.75% to 29.05%. Scanning electron microscopy demonstrated that NC-CS complexes possessed thin and smooth surfaces. The onset temperature, peak temperature, and conclusion temperature of CS were increased after complexation with NC, while the enthalpy showed no significant change. Moreover, the incorporation of NC resulted in increased solubility and transparency but decreased swelling power of CS. Notably, the slowly digestible starch (SDS) content increased from 32.01% to 58.07%, and CS with 5% NC exhibited the highest SDS content. The sum of SDS and resistant starch (RS) also increased (58.74%-69.73%), leading to reduced starch digestibility. In all, the changes in physicochemical properties and multi-scale structure of CS induced by NC resulted in decreased in vitro digestibility. This study provides foundations for the development of low glycemic index starch-based foods using NC.