Preparation Of High Content Soyasaponins By Column Chromatography And Crystallization

This paper studied the separation and purification of soyasaponins from the extract of soybean. It included two main processes, separation of the soyasaponins by column chromatography as well as crystallization.Firstly, we separated the soyasaponins from the soybean extract through column chromatography. Different types of macroporous resins named as ZTC-1, AB-8, HPD-100, HPD-300, HPD-600,ll#, 12# and 13# resins were used to separate soyasaponins. The sorption amount, recovery and content of soyasaponins had been examined. The results showed that 11# resin was the best. The optimal operation conditions were as follows: the feed concentration 6 mg/mL, and the load amount 10 mg/(mL resin), temperature 60℃, with elution procedure 1.5 BV pure water, 1.5 BV 20% ethanol, 2.5 BV 60% ethanol, respectively. The 60% ethanol elution fraction was collected and evaporated to dryness as the crude product. The characteristics of static and dynamic adsorption as well as desorption of soyasaponins on 11# resin were studied. The optimum conditions for static adsorption were as follows: water as solvent, pH 7.0 at the temperature 30℃, the saturated adsorption capacity of soyasaponins was 303.51 mg·g^-1. The effect of temperature on the dynamic adsorption was the same as on the static adsorption.Then, soyasaponins were further purified by crystallization in different solution such as different content of methanol, ethanol, acetone and isopropanol in water solution. The purity and recovery of soyasaponins by crystallization was examined. Results show that suitable crystallization conditions were as follows: solvent 40% ethanol, dissolved at reflux temperature, initial concentration 108 mg/mL, cooled to 20 ℃ for 24 h.In conclusion, the contents of the soyasaponins could be increased from 3.0% to 45% by column chromatography. The recovery was more than 90%. The content of soyasaponins could further be raised to more than 96.0% by crystallization, with a recovery more than 50%. The total recovery of soyasaponins was more than 45%.