Abstract: We compared the effects of membrane separation and alcohol precipitation on the separation efficiency and antioxidant activity of crude polysaccharides from Hericium erinaceus. Five different methods including alcohol precipitation, nanofiltration, nanofiltration + alcohol precipitation, microfiltration + nanofiltration and microfiltration + nanofiltration + alcohol precipitation were used in this study to obtain crude polysaccharides from the hot water extract from Hericium erinaceus, designated A-He P, B-He P, C-He P, D-He P and E-He P, respectively. The separation efficiencies of the five methods and the physicochemical properties and antioxidant activity of the crude polysaccharides were compared. Results showed that microfiltration + nanofiltration was the best method for the separation of crude polysaccharides. This method gave a polysaccharide yield of 10.08% and a purity was 43.01%, and recovered 80.34% of the polysaccharides in the extract. All five crude polysaccharides exhibited the typical absorption peaks of pyran-type glucan and β-glycosidic bond in the Fourier transform infrared (FTIR) spectra. In addition, these polysaccharides contained protein, and the protein content in B-He P was higher than that in C-He P, indicating that some proteins could be removed by microfiltration. Moreover, the crude polysaccharides had antioxidant capacity as evaluated by reducing power, ·OH, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays; D-He P had the best antioxidant capacity.

Key words: crude polysaccharides, microfiltration, nanofiltration, alcohol precipitation