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; 1:40-1:60), extraction time (X-2: 6-10 min), and ultrasonic temperature (X-3: 50-70 degrees C). The statistical analysis indicated the independent variables (X-2, X-3), the quadratic terms (X-2(2) and X-3) and the interaction between X-3 and X-1 had significant effects on the yield of polysaccharides (p < .05). The optimized conditions were 56 degrees 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%. (C) 2011 Elsevier Ltd. All rights reserved.