In vitro digestibility and emulsification properties of phytoglycogen octenyl succinate

This paper reports our recent studies on the in vitro digestibility and emulsification properties of an amphiphilic carbohydrate nanoparticle, phytoglycogen octenyl succinate (PG-OS). Phytoglycogen (PG), a glycogen-like alpha-d-glucan isolated from sugary-1 sweet corn endosperms, was subjected to octenyl succinate substitution to prepare PG-OS. Waxy corn starch octenyl succinate (WCS-OS) was also prepared as the reference. The degree of substitution (DS), molecular weight, particle size, dispersed molecular density, and zeta-potential of PG-OS and WCS-OS were determined. Transmission electron microscope (TEM) was used to image PG and its derivatives. In vitro digestibility and emulsification properties of PG-OS and WCS-OS were compared. The results showed that the dispersed molecular density of PG and PG-OS was much greater than that of WCS and WCS-OS. Zeta-potential of PG-OS decreased as the pH of dispersion increased. In general, the digestibility of PG and PG-OS was lower than that of WCS and WCS-OS at equivalent DS, suggesting the effect of glucan structure on glucan digestibility. At equivalent DS, PG-OS showed similar or even greater capability than WCS-OS to physically stabilize fish oil emulsions. This work revealed the potential of amphiphilic carbohydrate nanoparticles in the applications of emulsions.