High molecular weight soluble dietary fiber of corn bran exhibits stronger inhibitions in digestibility and short-term retrogradation of corn starch than low molecular weight soluble fiber

Starch-dietary fiber interactions regulate starch processing and digestion, though the effects of varying molecular weight dietary fibers remain insufficiently studied. This study investigates how corn bran-derived soluble dietary fibers (SDFs) with distinct molecular weights influence corn starch (CS) processing, retrogradation, and digestibility. Results revealed that adding 5 % ( W /W, based on the dry weight of CS) high molecular weight soluble dietary fiber (HM-SDF) or low molecular weight soluble dietary fiber (LM-SDF) significantly reduced amylose leaching, peak viscosity, retrogradation value, and retrogradation enthalpy during CS pasting. HM-SDF and LM-SDF decreased the thixotropic ring area by 55.8 % and 16.5 %, respectively, and inhibited the formation of ordered structures in CS. The HM-SDF-CS complex contained the least rapidly digestible starch at 68.26 %, indicating it more effectively slows starch digestion. These findings enhance our understanding of how SDF molecular weight distribution modulates starch-based foods, offering insights into potential applications for improved food processing and digestibility.