Effects of edible mushroom polysaccharides on the gel structure and digestive properties of mung bean starch: Synergistic driving mechanism of hydrogen bonding and electrostatic interactions.

Mung bean starch (MBS) is a key raw material for gel-based foods, but its application is hindered by rapid retrogradation, poor water-holding capacity, and high starch digestibility. This study investigated the effects of three mushroom polysaccharides (Flammulina velutipes, Hericium erinaceus, and Pleurotus eryngii) on the gel properties and in vitro digestibility of MBS, and elucidated the underlying mechanisms. All polysaccharides significantly reduced peak viscosity and gel hardness (p < 0.05) while increasing slowly digestible starch (SDS) content; Flammulina velutipes polysaccharide showed the strongest digestion-delaying effect. Structural analyses revealed that polysaccharides enhanced short-range ordered structures and promoted rough honeycomb networks. Mechanistically, polysaccharides bearing hydroxyl groups and negatively charged uronic acid residues inhibited amylose leaching and restricted granule swelling via non-covalent interactions including hydrogen bonding and electrostatic forces. These findings reveal structure-function relationships and support the development of low-digestibility, texture-improved starch-based foods.