Revealing the structure and functional properties of cationic phytoglycogen

This study investigated the structure-property relationships of cationized phytoglycogen (PG) modified with 2,3-epoxypropyl trimethylammonium chloride (GTAC) at varying degrees of substitution (DS). Characterization using ¹³C nuclear magnetic resonance (NMR) confirmed preferential grafting of quaternary ammonium groups at the C-2 position of glucose units, while enzymatic hydrolysis/tandem mass spectrometry (MS) revealed cationic group clustering near branch points adjacent to non-reducing ends. Rheology, thermogravimetric analysis, and interfacial stability analysis assessed differences in viscosity, elasticity, thermal stability, and interfacial tension modulation between PG and cationized derivatives. Density functional theory (DFT) simulations identified six reaction pathways, with pathway Ia showing the highest energy and β-epoxy group reactivity. The findings, highlighting DS-dependent properties, provide insights for optimizing PG derivatives for functional food applications like stabilized emulsions, fat mimics, and controlled release systems, emphasizing the need for precise modification.