Antioxidant and anti-inflammatory polyphenols and peptides of common bean (Phaseolus vulga L.) milk and yogurt in Caco-2 and HT-29 cell models

Common bean milks and their corresponding probiotic yogurts were developed and subjected to simulated gastrointestinal digestion before characterization and assessment of bioactivities. Only digestates fractions of molecular weight < 10 kDa showed strong cellular antioxidant activity and anti-inflammatory activity as demonstrated in suppressed TNF-alpha-induced IL-8 secretion in Caco-2 and HT-29 cell lines. Phenolic and peptide fractions were purified from the digestates. Yogurts showed significantly stronger cellular antioxidant and anti-inflammatory activities compared to their corresponding milks because of the significantly higher total and individual phenolic and peptide contents (P < 0.05). Eleven phenolic compounds and five amino acids/peptides were identified in the phenolic and peptide fractions, respectively using LC-MS/MS. Among them, two gamma-glutamyl-dipeptides are reported for the first time for their antioxidant and anti-inflammatory activities. Peptide fractions of yogurts containing higher concentrations of gamma-glutamyl-peptides showed stronger anti-inflammatory activity in Caco-2 cells than in HT-29 cells, suggesting the involvement of a peptide transporter PepT1.