Synergistic effects of ginseng polysaccharide on the structural and rheological properties of soy protein isolate-konjac gum emulsion gels: Potential application in quercetin delivery and dysphagia management.

This study investigated the effects of ginseng polysaccharides (GP) on the structural and rheological properties of soybean protein isolate (SPI)-konjac gum (KGM) emulsion gels. Isothermal titration calorimetry (ITC) revealed that the SPI-GP-KGM complexation is primarily driven by hydrogen bonding. Selective disruption experiments confirmed that hydrogen bonding, electrostatic, and hydrophobic interactions are all indispensable for the formation of the three-dimensional gel network. Mechanistic studies indicated that GP enhanced SPI-KGM interactions through hydrogen bonding via their hydroxyl and carboxyl groups. This increased the mean zeta potential of the complex solution from 18.2 mV to 21.1 mV, which suggested the formation of a more stable crosslinked structure. The enhanced stability of the complex particles allowed for more effective adsorption onto the oil droplet surface, which subsequently raised the zeta potential of the complex emulsion from 23.6 mV to 26.4 mV. The structure of the SPI-GP-KGM ternary system became more compact, forming a stable network gel structure during refrigeration. Electron microscopies confirmed the densification of the gel structure induced by GP, while rheological analysis revealed significantly enhanced gel strength (G' > G″), and exhibited shear-thinning behavior. Furthermore, the emulsion gel demonstrated remarkable stability under freeze-thaw cycles and centrifugation conditions and achieved a quercetin encapsulation rate of 67% while significantly improving its stability and bioaccessibility. International Dysphagia Diet Standardization Initiative (IDDSI) test suggested that the emulsion gel meets Grade 5 dysphagia diets. These results indicate that the incorporation of GP promotes the stable formation of emulsion gels and enables the efficient delivery of nutrients.