Effects of Processing Treatments on the Antioxidant Properties of Polysaccharide from Cordyceps militaris

Abstract

Abstract: The effects of deproteinization and drying methods on the antioxidant activities and physiochemical properties of C. militaris polysaccharide were evaluated. The results showed that the IC50 of crude polysaccharide (CMP)was similar with that of deproteined polysaccharide by sevag (CMP-D-S), but significant higher (p < 0.05)than that of deprotiened polysaccharie by enzyme (CMP-D-E)on DPPH· scavenging. The IC50 of CMP was significant higher (p < 0.05)than that of CMP-D-S and CMP-D-E on OH· scavenging. Deproteinization by sevag or enzymatic method could not improve the antioxidant activity of C. militaris polysaccharide. However, drying methods influenced the antioxidant activities of C. militaris polysaccharide. Polysaccharide dried by freeze drying (CMP-F)showed respectively 55.47 % and 61.99 % higher OH· scavenging capacity on IC50 than that dried by hot air drying (CMP-H)and spray drying (CMP-S). The IC50 of CMP-F was 56.23 % higher than that of CMP-S, but similar with that of CMP-H on ABTS· scavenging. The reducing power of CMP-F was respectively 20.10 % and 27.25 % higher than that of CMP-H and CMP-S at 6 mg/mL. Spectroscopy analysis showed the dried CMPs were similar in IR and UV absorption. However, the monosaccharide ratio of CMP was changed by drying techniques. Morphological analysis showed that CMP-F consisted mainly of fluffy powder with rough and porous surface, CMP-S was spherical particle with smooth surface, and CMP-H was pyknotic and similar to anomalistic stones. Freeze drying was a recommendable method for antioxidant polysaccharide preparation from C. militaris.