Purification and the antioxidant properties of saponins in soy molasses

Aiming to purify saponins from soybean molasses, single-factor experiments was carried out to optimize the extraction. The adsorption properties of AB-8 resin on saponins was studied, and the gradient elution was used to purify the saponins.The antioxidant properties of saponins were studied by the hydroxyl radical inhibition ability, superoxide radical scavenging capacity, and total antioxidant capacity.The optimized condition determined was that ethanol concentration of 75%, ratio of ethanol/water to raw material 25 ∶ 1, at 70 ℃ for 4 h, and the actual yield of saponins was ( 167.81 ± 6.19) mg/g.Meanwhile, the purity of saponins was 42.57% ± 2.34%. The adsorption rate and desorption rate of AB-8 resin on saponins were 68.50% and 49.99%, respectively.The temperature was 25 ℃ of column chromatography.Moreover, the purity of saponins reached to 73.21% by AB-8 resin column chromatography and 0 ~ 99% ethanol gradient elution. Among the saponins concentration of 0.5 ~ 1.5 mg/m L, the hydroxyl radical inhibition ability and total antioxidant capacity increased with the increasing concentration, the maximum was ( 47.25 ± 0.34) U/mg and ( 0.82 ± 0.04) mmol/g, respectively.Among 2.0~4.0 mg/m L, the superoxide radical scavenging capacity increased with the increase of concentration, the maximum was ( 28.93 ± 1.07) U/g.The study is valuable to the comprehensive utilization of soybean molasses and the purification of saponins.