Characterization of proanthocyanidins in pea (Pisum sativum L.), lentil (Lens culinaris L.), and faba bean (Vicia faba L.) seeds

The polymeric flavonoids, proanthocyanidins (PAs), were characterized in seeds of the grain legumes of pea (Pisum sativum L.), lentil (Lens culinaris L.), and faba bean (Vicia faba L.). PA subunit composition, quantitation and degree of polymerization were determined using reversed-phase high performance liquid chromatography-photodiode array detection after acid-catalysis in the presence of excess phloroglucinol (phloroglucinolysis). Liquid chromatography–mass spectrometry was used to confirm PA subunit identity. B-type PAs were found in all three grain legume species; however, the PA subunit composition varied among these legume seed crops. In the pea cultivars, the PA subunit composition was almost exclusively prodelphinidin (gallocatechin and epigallocatechin). Both procyanidin- and prodelphinidin-type flavan-3-ol subunits were abundant in the PAs of faba bean and lentil seeds tested. The seed PA content of these grain legumes ranged from approximately 270 to 650 mg/100 g fresh weight. These data show that seeds of specific cultivars of pea, faba bean and lentil can be a good dietary source of proanthocyanidins.