The research on metabolomics mechanism of calcium ion-induced whole black bean polyphenols and biological activities

The polyphenols and biological activities in whole black beans under Ca2+ pretreatment were studied. Metabolomics was used to identify the polyphenol metabolites, a total of 25 differential metabolites and 4 metabolic pathways were detected. In addition, Fourier Transform Infrared (FT-IR) and Ultraviolet–visible (UV–Vis) spectroscopy were used to characterize the polyphenol structure, free radical scavenging assays, enzyme inhibition experiments, and fluorescence spectroscopy were used to evaluate antioxidant capacity and hypoglycemic properties. The results showed that Ca2+ protected phenolic hydroxyl groups from substitution, reduced methoxylation and glycosylation of polyphenols. Moreover, Ca2+ enhanced antioxidant capacity by resisting oxidative damage, and enhanced hypoglycemic capacity by increasing the inhibitory activity of black bean polyphenols (BBPs) on starch digestive enzymes. These results preliminarily explored the antioxidant and hypoglycemic mechanisms of BBPs induced by Ca2+ from the viewpoint of metabolomics, and provided a theoretical basis for the enhancement of the functional properties of whole bean foods.