Impact of Ultrasound-Treated Emulsion Gels on the Structure of Purees for Oropharyngeal Dysphagia

This study investigated the effects of inulin concentration and ultrasonic homogenization on the particle size distribution and microstructure of oil-in-water emulsion gels stabilized with psyllium husk. These gels were then incorporated into meal purees formulated for individuals with dysphagia. Under ultrasound treatment, an increase in inulin from 0% to 20% reduced the average droplet size from 14.98 μm to 1.58 μm, indicating a synergistic effect between ultrasound treatment and inulin in reducing and stabilizing droplet size. The optimal formulation under ultrasound was 20% (w/w) inulin. Scanning electron and polarized light microscopy confirmed that ultrasonic homogenization improved emulsion integrity by minimizing droplet size and promoting encapsulation. Inulin-rich emulsion gels, when added to purees, reduced structural voids, improved matrix cohesion, and lowered expressible fluid content. Enzymatic assays showed enhanced inhibition of α-amylase and α-glucosidase, indicating increased resistance to oral enzymatic degradation. Importantly, substituting emulsion gels at 10% (w/w) did not compromise puree firmness. All formulations met International Dysphagia Diet Standardization Initiative (IDDSI) Level 4 requirements, confirming their suitability for individuals with oropharyngeal dysphagia (OD). These findings demonstrate the potential of psyllium husk-stabilized emulsion gels as innovative texture-modifying agents for dysphagia-friendly food development.