Optimized Extraction and Fermentation of Antioxidant Polysaccharides from Polygonatum odoratum

Abstract

Purpose: We wished to determine the optimal method for the extraction of polysaccharides with antioxidant activities from <i>Polygonatum odoratum</i>.Methods: Single-factor and orthogonal tests were applied to identify the best parameters for water extraction and fermentation. The solid-liquid ratio, temperature, and duration of water extraction were determined according to the total polysaccharide content. The fermentation temperature, agitation speed, inoculation amount, and fermentation time were investigated according to the optical density of Saccharomyces cerevisiae. The molecular weight distributions of water- and fermentation-extracted polysaccharides were determined by high performance gel permeation chromatography. The antioxidant activities of the polysaccharides were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS radical scavenging capacities, and ferric reducing antioxidant power (FRAP).Results: The optimum water extraction parameters were 80°C for 2.5 h with a 1:60 solid-liquid ratio. For fermentation, an 8% extraction volume was inoculated with <i>S. cerevisiae</i>. Optimal fermentation occurred at 28°C for 28 h, with an agitation speed of 180 r/min. The molecular weights of water- and fermentation-extracted polysaccharides were 2.067×10<sup>4</sup> and 9.475×10<sup>3</sup> Da, respectively. The DPPH, ABTS, and FRAP results demonstrated an obvious increase in antioxidant activity after fermentation.Conclusion: The fermentation extraction of <i>P. odoratum</i> may provide valuable materials for future cosmetic use.