Purification process and antioxidant activity of loquat polysaccharide

To study the process of purification of loquat polysaccharides by macroporous resin, the effect of deproteinization and polyphenol removal were compared among 6 kinds of macroporous resins, including D-101, AB-8, X-5, ADS-7, ADS-17, DM-130. The best macroporous resin was selected based on the adsorption rate of the protein and polyphenol, and the recovery rate of polysaccharide.The optimization process of loquat polysaccharide purification by the screening resin was studied through static and dynamic adsorption experiments.The antioxidant activity of polysaccharides before and after purified was determined by the method of FRAP and DPPH free radical scavenging.Compared with other 5 resin, ADS-7 resin was the most suitable one for preliminary purification of loquat polysaccharide.At room temperature ( 25 ℃) , the optimization process was as follows: the velocity was 1.2 BV/h, p H was 13, polysaccharide concentration was 24.59 mg/m L, sample volume was 5 BV, eluted by 10%ethanol to recovery of polysaccharide.Based on the optimization process, 85% polysaccharide could be recovered, the content of polysaccharides was up to 94.6% from 40.4%, and purification multiple was 2.34 times.The EC50 of DPPH free radical of loquat polysaccharides after purified was down to 1.64 mg/g from 4.21 mg/g. Conclusion: the macroprous resin can be used to purify the loquat polysaccharides, and the purified polysaccharides had higher scavenging active of free radical than the crude polysaccharides.