Designing a multiphase Pickering emulsion to control its rheological behavior and digestibility for the elderly with dysphagia and glucose metabolism disorders.

Coordinated regulation of rheological properties and digestibility is critical for developing personalized liquid nutrition for elderly individuals with different levels of dysphagia and glucose metabolism disorders. In this study, oil-in-water (O/W) Pickering emulsions stabilized by whey protein isolate (WPI)/oxidized starch nanoparticles (3 wt%, WPI: oxidized starch: EGCG = 7:1:0.2) were incorporated into yam starch (2.8% w/w)/guar gum (0.8% w/w) water-in-water (W/W) emulsions to construct hierarchical multiphase Pickering emulsions. The rheological properties and digestibility of the multiphase Pickering emulsions were synergistically regulated by tailoring the digestion resistance of WPI/oxidized starch nanoparticles based interfacial film, together with the droplet size and addition amount of the O/W Pickering emulsion. The optimized WPI/oxidized starch nanoparticles exhibited a particle size of 373.53 nm, a contact angle of 90.84°, and reduced the predicted glycemic index (pGI) and WPI hydrolysis degree by 33.49% and 18.80%, respectively. The droplet size of the O/W Pickering emulsions ranged from 1.76 ± 0.02 μm to 5.48 ± 0.33 μm. As the droplet size and O/W Pickering emulsion amount increased, the intermolecular interactions between interfacial nanoparticles were enhanced. Compared with the yam starch/guar gum system, the viscosity of the multiphase Pickering emulsion exhibited a 195.8% increase in viscosity (205.71 increased to 608.65 mPa·s) and a 42.78% reduction in pGI (91.57 reduced to 52.40). These findings demonstrate that hierarchical multiphase Pickering emulsions provide an effective strategy for simultaneously improving rheological properties and reducing starch digestibility, offering promising potential for personalized liquid nutrition for elderly individuals with different levels of dysphagia and glucose metabolism disorders.