Antioxidant capacities of mannans and glucans are related to their susceptibility of free radical degradation

• Antioxidant abilities of mannans and β-glucans against OH did not exceed 14%.
• Antioxidant ability of CM-glucan against OH was significantly higher (65%).
• The chelation abilities of yeast mannans and β-glucans on Fe2+did not exceed 13%.
• Mannans and glucans were degraded by OH, no degradation was obtained by DPPH.

Microbial and plant polysaccharides in nature are frequently exposed to oxidative burst. They may act as antioxidants buffering the radical attack. This paper presents antioxidant properties of prepared yeast mannans, commercial β-glucans as well as the chemically prepared carboxymethylated β-glucan (CM-glucan). The hydroxyl radical antioxidant assay and the DPPH radical-scavenging assay were used. Yeast mannans and β-glucans (1.6 mg mL−1) showed antioxidant capacities against OH up to 14.1%, while CM-glucan was significantly higher antioxidant (65.4%). In the DPPH assay, the antioxidant capacities of yeast mannans and β-glucans (1.0 mg mL−1) were lower and reached up to ∼6.5%. All polysaccharides tested were effectively degraded by OH and the presence of salicylate considerably inhibited their degradation. Measure of Fe2+ chelation revealed less than 13.1% effectivity for all polysaccharides. In all antioxidant and degradation experiments the yeast mannans showed very similar results to commercial β-glucans. The antioxidant capacities of polysaccharides may be assessed by simple HPLC monitoring.