Interaction between Hovenia dulcis polysaccharides and dihydromyricetin: A systematic study on structure, in vitro digestion, and functionality.

Polysaccharide-flavonoid interactions are integral to the health-promoting effects of plant-derived food. This study investigated the structural characteristics, in vitro digestive stability, prebiotic potential, and in vitro fermentation characteristics of covalent (H70D-C) and non-covalent (H70D-NC) complexes formed between Hovenia dulcis polysaccharides (HDPs70) and dihydromyricetin (DMY), with particular emphasis on the influence of the binding mode. The results showed that H70D-C exhibited a significantly greater DMY-binding capacity (580.41 ± 1.12 mg DMY/g) than H70D-NC (421.06 ± 1.36 mg DMY/g). Infrared spectroscopy confirmed that covalent bonding formed ester bonds, and hydrogen bonds were the main driving force of non-covalent interactions. The covalent complex H70D-C exhibits superior enzyme inhibitory activity, antioxidant activity and thermal stability. The results of in vitro digestion showed that all components could pass through the gastrointestinal tract smoothly, and HDPs70 could effectively protect DMY throughout the digestion process. Moreover, all three polysaccharides promoted the growth of beneficial microbes. DMY incorporation increased the abundance of Bifidobacterium and decreased the level of Escherichia-Shigella, and both binding modes markedly improved the gut microbial community structure. Collectively, these findings support the development of functional foods derived from Hovenia dulcis.