Plant protein-starch-based gels for design of dysphagia foods: Combining rheology and tribology with IDDSI

With the growing prevalence of dysphagia among older adults, increasing attention is being paid to the rheological and tribological design of easy-to-swallow foods. This study investigated the potential of using sustainable proteins such as pea protein in a pea protein-pea starch-based model food matrix to understand how textural characterization can help to design dysphagia-friendly food applications. Rheological and tribological properties of pea protein (PP, 0-10 wt%) and pea starch (PS, 0-7.5 wt%) were studied followed by evaluation of these pea starch-pea protein (PS-PP) matrices using International Dysphagia Diet Standardization Initiative (IDDSI) framework. Results confirmed that starch addition ≥2.5 wt% promoted the transition of PS–PP matrices from fluid-like to solid gel-like behavior. Moreover, all PS–PP matrices exhibited lower friction coefficients (μ) than buffer, indicating improved lubrication during swallowing. In particular, gels with high protein (10 wt%) and high starch contents (7.5 wt%) displayed a relatively flat frictional response over the investigated speed range and very low boundary friction (μ ≤ 0.01). Overall, PS–PP matrices enhanced lubrication through the combined effects of interfacial boundary-layer formation and the development of hydrated, structured biopolymer networks that stabilized the lubricating film in the contact region offering viscous lubrication. The IDDSI testing confirmed that the matrices met the criteria for levels 2, 3, 4, and 6, indicating a broad applicability of these matrices across dysphagia severity levels. These findings demonstrate that PS–PP matrices hold promise as customizable dysphagia alternative protein-based sustainable food bases with tunable texture, lubrication and flow properties.