Melanoidins from Shanxi aged vinegar: Characterization and behavior after in vitro simulated digestion and colonic fermentation

This study aims to elucidate the structure, physicochemical properties, and potential behavior of vinegar melanoidins (VM) during digestion and intestinal microbial fermentation in vitro. Our findings revealed that VM mainly consisted of carbohydrates. The particle size (166.46 ± 10.06 nm) of VM was significantly larger than that of model melanoidins (MM, 20.69 ± 0.05 nm). VM exhibited stability in vitro digestion process. However, the carbohydrate contents and Mw were reduced. Total phenol content (TPC), total flavonoid content (TFC), antioxidant capacity and SCFAs were significantly increased after colonic fermentation. TPC and TFC were 79.48 ± 9.52 mg GAE/g DW and 0.422 ± 0.024 mg RE/g DW at 48 h. In addition, VM exhibited intestinal modulatory effects on the microbiota by promoting an increase in beneficial bacteria including Firmicutes and Bifidobacterium. Collectively, these results suggest that VM as a potential prebiotic can be applied in the field of functional food.