An Untargeted Liquid Chromatography Mass Spectrometry Method for Identifying and Quantifying Saponins in Pulses

Untargeted liquid chromatography mass spectrometry, with negative and positive ionization and data-dependent acquisition, was applied to investigate the type and quantity of saponins present in raw and cooked seeds of five legume species produced in Mediterranean countries. Overall, 15 saponins were detected, and their fragmentation pattern were reported. Three of them were found in all samples, namely, soyasaponins I, αg, and βg. Results show significant differences among species and among different varieties. Soyasaponins βg and I were the most frequent saponins with a concentration range of 15-395 mg/100 g in raw seeds. After soaking and cooking, the majority of saponins reduced their concentration by 50-100%, whereas soyasaponins I and V reported an important concentration increase in beans and cowpeas. Results provide new information on the types and amounts of saponins consumed with pulses in the human diet.