Particulate structure of phytoglycogen nanoparticles probed using amyloglucosidase

Phytoglycogen is a plant-based, high-density carbohydrate nanoparticle that can be used as a starting material for preparing novel functional nano-constructs. In this study, the particulate structure of phytoglycogen was probed using amyloglucosidase hydrolysis, with amylopectin of waxy corn starch as a reference. Glucose release was monitored; molar mass, root mean square (RMS) radius, and dispersed molecular density were evaluated using multiangle laser-light scattering. The goal was to reveal the structural features of phytoglycogen nanoparticles. After extended amyloglucosidase hydrolysis, the total glucose release of phytoglycogen was lower than that of amylopectin. At the initial stage of hydrolysis, however, glucose was released at a higher rate from phytoglycogen, suggesting a dense distribution of nonreducing ends at the surfaces of nanoparticles. The reduction of molar mass and RMS radius caused by amyloglucosidase hydrolysis were much lower for phytoglycogen than for amylopectin. The dispersed molecular density of amylopectin remained at about 60 g/mol nm3 during hydrolysis. In contrast, the density of phytoglycogen decreased from about 1200 to 950 g/mol nm3, suggesting a density increment towards the external region of nanoparticle.