Molecular Interactions of Resistant Dextrin with Wheat Starch and Gluten: Structural Dynamics and Macromolecular...

Refined wheat staple foods are widely criticized for low dietary fiber and high postprandial glycemic response, making soluble dietary fiber fortification a promising strategy for cereal improvement. This study investigated how resistant dextrin (RD) modulates wheat starch, gluten, dough, and bread quality through multiscale interactions. In wheat starch, 6% RD gave the best overall balance, reducing 14-day retrogradation from 57.2% to 48.6%, delaying gelatinization, and restricting amylose diffusion, with hydrogen bonding identified as a major contributing interaction. In gluten, RD increased water-holding capacity but weakened network integrity, as evidenced by reduced moduli, a shift in thiol-disulfide balance, secondary-structure redistribution (increased β-sheet, decreased α-helix/β-turn), and suppressed glutenin polymerization, yielding a looser microstructure. In dough, SEM and rheological results suggested that moderate RD (4-6%) may form a hydrated, polysaccharide-rich phase that fills structural voids and improves matrix continuity, partially offsetting gluten weakening and enhancing viscoelasticity. Overall, this study establishes a quantitative relationship between RD addition level, multiscale macromolecular interactions in wheat matrices, and the processing performance and quality of bakery products.