Dendrobium officinale polysaccharide modulates hydrogen-bond reorganization in mung bean starch/flaxseed protein gels: Engineering texture design for dysphagia diets

Dendrobium officinale polysaccharide (DOP) was introduced as a novel modulator to address the insufficient texture tunability of plant-based (mung bean starch MBS/flaxseed protein FP) gels for dysphagia diets. The formation mechanism and properties of composite gels with DOP (0-0.12%) were investigated. Incorporating DOP reconfigured the ternary network through competitive hydration and intermolecular hydrogen bonding, leading to concentration-dependent properties. At 0.03% DOP, gel hardness decreased to 73.31 g, corresponding to IDDSI Level 5. At 0.06%-0.09% DOP, water-holding capacity (WHC) increased from 61.9% (control) to 74.8%, and cohesiveness rose 3.0∼3.8 times, enabling IDDSI Level 6 classification. At 0.12% DOP, hardness peaked at 208.16 g with reduced adhesiveness (6.24 g s), meeting the requirements of IDDSI Level 7. LF-NMR analysis revealed an increased proportion of immobilized water with stronger binding. Spectroscopy and microscopy confirmed hydrogen-bond reorganization and the corresponding microstructural shift from a porous to an irregular, thin-walled network. This work elucidates the mechanism of DOP-mediated gelation, providing a rational strategy for designing tailored dysphagia foods.