Preparation Of Group B Soyasaponins From Soybean Germ

Soyasaponins are oleanane triterpenoids that are amphiphilicmolecules. Soyasaponins are classified into two main groups A and B.Group A soyasaponins are much bitter than Group B. This paper study onisolation and purification of Group B soyasaponins includingoptimization of extraction conditions, purification by macroporous resinand crystallization.1. optimizing ethanol concentration, solid to liquid ratio, extractiontime and extraction temperature. optimum extraction conditions: solid toliquid ratio1:20, extract3h at70℃with70%ethanol. The extract rate ofGroup B soyasaponins is90%. Soybean germ contain1.71%Group Bsoyasaponins.2. Eight macroporous resins including D101, NKA, ZTC-1, HP20,HZ-818, HPD-100, HZ-816and AB-8were investigated. The adsorptioncapacities, desorption capacities and desorption ratios of Group Bsoyasaponins on different macroporous resins were compared. Theadsorption and desorption capacities, and the desorption ratios ofHPD-100resin were15.698mg/g,14.12mg/g and90.5%, respectively, and these parameters in NKA resin were14.813mg/g,13.99mg/g and97.1%, respectively. The adsorption and desorption capacities ofHPD-100on Group B soyasaponins resin was higher than on NKA, butNKA had a better desorption ratio. Thus, NKA resin was selected forGroup B soyasaponins separation. The optimum conditions were asfollows: the initial concentration is1.69mg/ml, the NKA resin wasflushed with2BV20%aqueous ethanol to remove highly polarcomponents in the extract, and then flushed with2.5BV80%aqueousethanol. The purity of total saponins was55.6%with a recovery of75.2%.The purity of Group B soyasaponins was20%with a recovery of88%.3. Then Group B soyasaponins was further purified by a two-stepcrystallization. The solvent of crystallization including ethanolmethanol isopropanol and deionized water were investigated. Theoptimum solvent of crystallization is deionized water. In the first step,initial concentration of Group B soyasaponins10mg/ml, the rate of falltemperature3℃/h, final temperature20℃, Crystallization time0h wereselected as crystallization condition. In the second step, initialconcentration of Group B soyasaponins15mg/ml, the rate of falltemperature3℃/h, final temperature20℃, Crystallization time0h wereselected as crystallization condition. The purity of Group B soyasaponinswas83.19%by two-step crystallization. All processes were followed by a large-scale, The product containing79.23%Group B soyasaponins wasproduced with a recovery14.04%.