Gum tragacanth/konjac glucomannan emulsion gels for dysphagia: Rheo-tribology and β-carotene stability

All-polysaccharide GT/KGM emulsion gels serve as multifunctional dysphagia carriers. • Increasing GT strengthened the network, immobilized water, and improved lubrication. • IDDSI classification shifted from Level 4 to Level 6 with increasing GT concentration. • GT/KGM gels significantly protected β-carotene against time, heat, light, and pH stress. Texture-modified foods for dysphagia should provide bolus safety, oral comfort, structural stability, and nutritional value, but many current systems rely mainly on thickening or pureeing and have limited capacity to protect lipophilic nutrients. In this study, gum tragacanth/konjac glucomannan (GT/KGM) emulsion gels were developed for dysphagia. The gels were prepared with a fixed KGM concentration of 0.2% (w/v) and GT concentrations of 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% (w/v), corresponding to KG1-KG5. Then, the resulting gels were evaluated for stability, structure, water distribution, rheological and tribological behavior, IDDSI classification, and β-carotene retention. Experimental results showed that increasing GT concentration improved droplet dispersion and shifted part of the relatively mobile water toward network-immobilized water. All samples exhibited solid-like viscoelastic behavior and shear-thinning flow, indicating deformable but structured gel networks. Tribological analysis showed Stribeck-like lubrication, with GT-rich formulations exhibiting lower friction at intermediate and high sliding speeds. TPA combined with IDDSI testing revealed a GT-driven transition from Level 4 (KG1) to Level 5 (KG2-KG3) and Level 6 (KG4-KG5). Both KG4 and KG5 met IDDSI Level 6. KG4 had lower hardness, gumminess, chewiness, and springiness than KG5. β-Carotene-loaded gels maintained high retention under heating, light exposure, and different pH conditions. These results show that all-polysaccharide emulsion gels can control texture for swallowing and protect lipophilic nutrients. They may be used to develop foods for people with dysphagia in the future. Download: Download high-res image (137KB) Download: Download full-size image GT/KGM emulsion gels for dysphagia-oriented texture control, oral lubrication, and β-carotene protection. GT and KGM were used to construct all-polysaccharide emulsion gels with corn oil as the lipid phase. Increasing GT concentration reinforced the gel network, improved water retention and reduced friction during simulated oral processing, supporting IDDSI-based swallowing suitability. The structured lipid phase further served as a protective carrier for β-carotene under environmental stresses. These results suggest that GT/KGM emulsion gels can integrate swallowing safety, oral comfort and lipophilic nutrient protection for dysphagia-oriented food design.