Abstract:

In this study, we optimized key conditions for the water extraction and ethanol precipitation of polysaccharides from the edible fungi, Pleurotus eryngii, Lentinula edodes, Flammulina velutipes and Boletus edulis Bull using single factor and orthogonal array design methods and compared the reducing power of the products obtained. The results showed that the optimum values of extraction temperature, material-to-water ratio (g/mL), length of extraction and ethanol concentration were 90 ℃, 1:30, 1 h and 95% for Pleurotus eryngii polysaccharide extraction, 90 ℃, 1:20, 3 h and 85% for Lentinula edodes polysaccharide extraction, 80 ℃, 1:20, 2 h and 95% for Flammulina velutipes polysaccharide extraction, and 70 ℃, 1:40, 4 h, 95% for Boletus edulis Bull polysaccharide extraction, respectively. Under these optimum conditions, the corresponding polysaccharide yields were 3.89%, 5.93%, 2.79% and 9.48%, respectively. All of these four fungal polysaccharides had reducing power positively correlated with concentration. The reducing power of Boletus edulis Bull polysaccharides was the strongest. Also, the yield of Boletus edulis Bull polysaccharides was the highest. These results demonstrate Boletus edulis Bull appear to be a promising edible fungus.

Key words: edible fungi, polysaccharides, optimization, reducing power