The Bioconversion And Antioxidant Activity Analysis Of Xanthoceras Sorbifolia Husk Saponin

The husk of Xanthoceras sorbifolia Bunge is the main waste of X. sorbifolia after oil extracting processing, containing many kinds of chemical constituents. The saponins are the main active component, which have unique pharmacological properties of anti inflammatory, anti tumor, inhibition of HIV protease, and can improve the capability of learning and memory. Therefore, deeply development and high value application of the X. sorbifolia husk resources will have important effect on the the use of food, medicines and health products industries. In this thesis, the extraction and purification of the X. sorbifolia husk saponin was firstly optimized, and then the saponin was hydrolyzed by biotransformation process. The antioxidant activities of hydrolysis products were further analyzed and discussed.The husk of X. sorbifolia saponin was extracted by ethanol refluxing method, and the extracting ratio was 2.64%. Then, AB-8 macroporous resin was used for the separation and purification of the X. sorbifolia husk saponin, and the effects of sample solution concentration, ethanol volume fraction, eluent flow rate and NaOH mass fraction were examined for the orthogonal design. Furthermore, the operating parameters were optimized to a overall consideration of purity and recovery, when the sample solution concentration was 30 mg/mL, ethanol volume fraction was 70%, eluent flow rate was 2.0 BV/h and NaOH mass fraction was 0.20%. As a result, the purity of the X. sorbifolia husk saponin was 67.81%, and the recovery ratio was 64.04%.The strain Aspergillus niger 848 was used as an enzyme resource to hydrolyze the husk of X. sorbifolia saponin. The effects of enzymolysis time, enzyme dosage, enzymolysis temperature, and pH on the enzymatic hydrolysis process were determined and optimized by orthogonal experiment. It was indicated that the optimal enzymatic hydrolysis conditions were as followed: hydrolysis time was 24 h, the amount of enzyme was 0.06 m L, enzymatic hydrolysis temperature was 40 ℃, and pH= 4.TLC comparative analysis was used to analysis the X. sorbifolia husk saponin products before and after hydrolyzing. There are four kinds of products with migration rates of 0.59, 0.68, 0.75 and 0.93, respectively. The antioxidant activity of four products were determinated using the DPPH method, FRAP method and Fenton method.UPLC and IR were used to analysis the structure changes of the X. sorbifolia husk saponin before and after enzymatic hydrolysis. It can be clearly seen that in the process of biotransformation, four products were generated and the structure of the X. sorbifolia husk saponin was changed to some extent.