Effects of Qingke β-glucan with different molecular weights on pasting, gelation, and digestive properties of rice starch

Abstract

This study aimed to investigate the impact of Qingke β-glucan (QBG) concentrations and molecular weights (MWs) on rice starch (RS). With the increasing concentrations and MWs, the pasting properties and gelatinization enthalpy of RS/QBG suspension decreasing was observed by using rheometer and differential thermal scanning analysis, respectively, which was consistent with the results of X-ray diffraction. In Infrared spectrum, QBG combined with leached amylose via hydrogen bonds, thus preventing the reaggregation of RS particles and inhibiting the short-term retrogradation of RS. The results of scanning electron microscopy and confocal laser scanning microscopy suggested that interaction between QBG and RS changed RS microstructure, reduced the leached amylose of the starch, and thus altered RS/QBG digestibility that the digestion rate of RS/QBG decreased with the incrementing QBG MWs at in vitro simulated experiments. These results provide further understanding and expand potential application to starch-based foods.

Keywords

• Qingke β-glucan
• Molecular weights
• Confocal laser scanning microscopy
• Pasting properties
• In vitro starch digestibility