Based on the phenolic profiles obtained by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-DAD-ESI/MS), 24 common bean samples, representing 17 varieties and 7 generic off-the-shelf items, belonging to ten US commercial market classes can be organized into six different groups. All of them contained the same hydroxycinnaminic acids, but the flavonoid components showed distinct differences. Black beans contained primarily the 3-O-glucosides of delphinidin, petunidin and malvidin, while pinto beans contained kaempferol and its 3-O-glycosides. Light red kidney bean contained traces of quercetin 3-O-glucoside and its malonates, but pink and dark red kidney beans contained the diglycosides of quercetin and kaempferol. Small red beans contained kaempferol 3-O-glucoside and pelargonidin 3-O-glucoside, while no flavonoids were detected in alubia, cranberry, great northern, and navy beans. This is the first report of the tentative identification of quercetin 3-O-pentosylhexoside and flavonoid glucoside malonates, and the first detailed detection of hydroxycinnamates, in common beans.
Keywords: 24 Common beans; Anthocyanin; Glycosylated flavonols; HPLC-DAD-ESI/MS; Hydroxycinnamates; Phaseolus vulgaris L.: Market classes; Polyphenol profile.