Effect of Acid Hydrolysis on the Rheology of Phytoglycogen Nanoparticles

Phytoglycogen is a natural polysaccharide produced in the form of compact 35 nm diameter nanoparticles by some varieties of plants such as sweet corn. The highly-branched, dendrimeric structure of phytoglycogen leads to interesting and useful properties that make the particles ideal as unique additives in personal care, nutrition and biomedical formulations. One such property is the unusual polysaccharide rheology of aqueous dispersions of phytoglycogen nanoparticles [1]. When added to water, the zero-shear viscosity of the dispersions remains small up to large concentrations (~20% w/w). For higher concentrations, the zero-shear viscosity increases dramatically, reaching values that exceed that of water by more than a factor of 10⁶ at the highest concentrations of 30% w/w. We have used acid hydrolysis to partially digest the phytoglycogen nanoparticles, which not only reduces their diameter, but also removes the hairy chains on the outer surface of the particles thereby altering the interaction between particles. We compare the concentration dependence of the zero-shear viscosity of the smaller, acid hydrolyzed particles to that of the native particles. These results suggest new applications for the acid hydrolyzed particles.

[1] H. Shamana et al., Soft Matter 14, 6496 (2018).