The saponin content and composition of sweet and bitter lupin seed

The seed of six species of lupin: Lupinus albus (sweet and bitter), L angustifolius (sweet and bitter), L luteus (sweet and bitter), L hispanicus, L consentinii (lagao/faro) and L mutabilis were analysed for total saponin content and sapogenol composition. The saponin content ranged from 0 to 470 mg kg−1 with none being detected in the L albus species; 56·7 and 68·3 mg kg−1 in the L luteus (sweet and bitter respectively); 107·9 mg kg−1 in L mutabilis; 302·7 mg kg−1 in L hispanicus; 216·1 mg kg−1 in the L consentinii and 270·1, 469·5 mg kg−1 in L angustifolius (sweet and bitter, respectively). Three saponins were detected, one containing soyasapogenol B and considered to be identical to soyasaponin 1, the other two being bisdesmosides of soyasapogenol A. The ratio of the two sapogenols in the overall saponin mixture varied between 0·3:1 and 3·1:1.