Comparison of open-column and high-performance gel permeation chromatography in the separation and molecular-weight estimation of polysaccharides

Dynamic high-pressure appears to be an alternative approach to physical modification of polysaccharides aimed to improve their functional characteristics. The objective of our study was to evaluate the effect of dynamic high-pressure microfluidization (DHPM) treatment on the physicochemical properties and antioxidant activities of Mesona chinensis Benth polysaccharide (MP). The results indicated that the contents of total sugar and uronic acid in DHPM-treated polysaccharide samples (DMP) were increased, and protein content in DMP was significantly decreased after DHPM treatment. The molecular weights of MP and DMP were 1.58 × 105 Da and 1.64 × 105 Da. MP and DMP were composed of Gal, Xyl, and GalA in a molar ratio of 2.8: 5.5: 2.4 and 3.8: 7.4: 3.0, respectively. The antioxidant activities of MP were slightly promoted after DHPM treatment. Moreover, DHPM treatment leads to changes in the morphology of polysaccharide. The surface appearances of DHPM-treated polysaccharide samples showed a slightly curly surface compared to original polysaccharide by SEM analysis. No considerable changes were observed in the structure between the MP and DMP by FT-IR. The results provide useful information for future application of MP, and show DHPM treatment can improve the antioxidant activity of polysaccharides.