Abstract / Summary
This study investigated digestion-driven changes in polyphenol content, Maillard reaction products, and cholinesterase inhibitory activity in mushroom-, asparagus-, leek-, and sea buckthorn-based vegan soups. These polyphenol-rich, plant-based soups were previously developed and evaluated by our research team as dietary components intended to support cognitive health. However, little is known about how gastrointestinal digestion and colonic fermentation affect the bioactivity of these soups. Targeted UHPLC–ESI–MS analysis demonstrated substantial matrix-dependent differences in polyphenol composition, with mushroom soup containing the highest levels of gallated catechins and exhibiting the strongest cholinesterase inhibitory activity. Simulated gastrointestinal digestion significantly altered polyphenol profiles and biological activity. While gastric digestion induced only minor changes, the small-intestinal phase reduced the levels of ellagic, ferulic, and chlorogenic acids, as well as selected flavonols, accompanied by decreased AChE and BChE inhibition and increased IC₅₀ values. In contrast, colonic fermentation promoted the regeneration of gallic and caffeic acids, gallated catechins, and flavonol aglycones, resulting in enhanced cholinesterase inhibition and stronger enzyme-ligand interactions. Acrylamide and 5-hydroxymethylfurfural concentrations decreased progressively throughout digestion, with the greatest reductions observed during colonic fermentation. Kinetic and thermodynamic analyses indicated spontaneous and predominantly exothermic formation of enzyme-ligand complexes with apparent thermodynamic parameters. These findings demonstrate that gastrointestinal digestion, particularly microbiota-mediated colonic fermentation, is a key determinant of polyphenol bioactivity in complex plant-based food matrices. The results highlight the potential of vegan soups as food matrices that retain selected bioactive compounds during simulated digestion.