Effects of different extraction temperatures on the physicochemical properties of bioactive polysaccharides from Grifola frondosa

This study examined the effects of different extraction temperatures (70°C, 100°C and 121°C) on the physicochemical properties of water soluble polysaccharides (WSP; GF70, GF100 and GF121, respectively) from Grifola frondosa (GF) fruiting bodies, and evaluating their effects on nitric oxide (NO) production in lipopolysaccharide-stimulated RAW264.7 macrophages. Results showed that GF121 had the highest yield. GF70, GF100 and GF121 contained a similar monosaccharide composition and the predominant monosaccharide was glucose. These polysaccharides contained two major macromolecular populations; the high molecular weight population showed a clear trend of reduced molecular weight with increasing extraction temperature. GF121 contained the highest amount of (1→3, 1→6)-β-d-glucans, while the degree of branching in all samples was similar. GF WSP possessed NO inhibitory activity, and the strongest was GF121. This study concludes that WSP are good sources of food ingredients, and high temperature extraction could improve the quantity and quality of GF WSP.