Understanding the mechanisms of β-glucan regulating the in vitro starch digestibility of highland barley starch under spray drying: Structure and physicochemical properties

This study investigated the effects of β-glucan (0–6%) on the physicochemical properties, structure, and in vitro digestibility of highland barley starch (HBS) under spray drying (SD). SD significantly enhanced the inhibitory effect of 6% β-glucan on the in vitro digestibility and glucose diffusion of HBS. After SD, the addition of β-glucan at 4% and 6% concentration significantly increased the pasting temperatures of starch while decreased the rheological properties. Thermal properties demonstrated that β-glucan improved the thermal stability and residue content of HBS at 600°C, lowered its maximum loss rate, and maintained its thermal stability after SD. Structural properties showed that β-glucan affected greatly on amorphous regions of HBS after SD. Additionally, β-glucan dispersed more evenly in the starch system and experienced hydrogen bonding with starch after SD. This study presents a novel approach to enhancing the inhibitory effect of β-glucan on starch digestion.