Development and characterization of polysaccharide–protein composite gels for dysphagia-friendly applications

Developing dysphagia-oriented foods requires texture-modified gel matrices with adequate structural integrity and stable viscoelastic properties, whereas single-thickener systems often provide limited control over overall gel performance. Here, we developed and characterized a fermented polysaccharide-protein composite gel system based on high-acyl gellan gum (HA-GG) and hydroxypropyl methylcellulose (HPMC). Candidate food-grade polysaccharides permitted under GB 2760-2014 were first screened, followed by single-factor experiments and a three-factor, four-level L16 (4³) orthogonal design to optimize formulation composition and fermentation time. Among twelve candidates, only HA-GG and HPMC satisfied all screening criteria. The optimal condition was 0.3 wt% HPMC, 0.3 wt% HA-GG, and 13 h fermentation, and all three factors significantly affected screening performance. Under the optimized condition, gel hardness increased at moderate polysaccharide incorporation but declined at higher levels. Rheological analysis confirmed elastic-dominant gel behavior across formulations, while scanning electron microscopy revealed improved network continuity at moderate incorporation but excessive compactness at higher levels. These findings demonstrate that balanced polysaccharide-protein network organization is critical for the rational design of stable fermented gel matrices with potential relevance to dysphagia-oriented food applications.