Proanthocyanidin profile of cowpea (Vigna unguiculata) reveals catechin-O-glucoside as the dominant compound

► Diverse cowpea varieties screened for tannin profile and content. ► Green and white cowpeas contain no tannins. ► Monomeric proanthocyanidins constitute 46% of cowpea tannins. ► Catechin-O-glucoside the single dominant compound (88% of monomers).