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 (X: 1:40-1:60), extraction time (X: 6-10min), and ultrasonic temperature (X: 50-70°C). The statistical analysis indicated the independent variables (X, X), the quadratic terms (X and X) and the interaction between X and X 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 8.4min. Under these conditions, the experimental yield of polysaccharides was 15.48%, which was well matched with the predictive yield of 15.53%.