Optimization of ultrasonic-assisted extraction of water-soluble polysaccharides from Boletus edulis mycelia using response surface methodology

An ultrasound-assisted procedure for the extraction of water-soluble polysaccharides from the submerged-cultured mycelia of Boletus edulis was investigated using response surface methodology (RSM). Three independent variables were ratio of dried mycelia to water (X1: 1:40–1:60), extraction time (X2: 6–10 min), and ultrasonic temperature (X3: 50–70 °C). The statistical analysis indicated the independent variables (X2, X3), the quadratic terms ( X 2 2 and X 3 2 ) and the interaction between X3 and X1 had significant effects on the yield of polysaccharides (p < .05). The optimized conditions were 56 °C, 1:55 of ratio of dried mycelia to water, and a time of contact of 8.4 min. Under these conditions, the experimental yield of polysaccharides was 15.48%, which was well matched with the predictive yield of 15.53%.