Phenolic Acid Metabolites Generated via Lactic Acid Bacteria Fermentation of Wild Blueberries: Comparison to Circulating Gut-Derived Metabolites from Endogenous Fermentation

were used to track the structural changes in polyphenolic composition in wild blueberry treatments after 72 h fermentation, and to compare metabolites from exogenous fermentation to those reported to be produced by human gut-derived catabolism. Shifts in the profiles of flavonoids, anthocyanins, proanthocyanidins, phenolic acids, and phenolic acid conjugates (some putatively identified for the first time in wild blueberries) were quantified. While glucuronide and sulfate conjugates of phenolic acids (which rely on human enzymes) are not produced in vitro, exogenous fermentation can, depending on the conditions, replicate a broad range of the bioactive phenolic acids generated by endogenous fermentation of wild blueberries in the human gut. Exogenous fermentation may therefore yield more standardized and physiologically relevant phenolic profiles than an unfermented blueberry extract for use in translational preclinical research on berry health benefits.