Extraction optimization of the polysaccharide from Adenophorae Radix by central composite design.

The central composite design (CCD) was applied to optimize the water extraction of the polysaccharide from Adenophorae Radix in the paper. The three variables of extraction temperature (X1), extraction time (X2) and ratio of water to raw material (X3) were investigated by single factor analysis first. Since the presence of active polysaccharides and the imperfect of its extraction, the purpose of the paper was to evaluate the effects of selected variables on the yield of polysaccharide, which was expected to obtain the maximum yield. By variance and regression analysis, the quadratic regression equation was established as a predicted model. The R(2) of 0.9825 indicated that the equation was well-fitted. The optimal conditions were 72.5°C, 133min, 1:35 (g/mL) and the predicted maximum yield of the polysaccharide was 5.78%. The predicted value was verified in triplicates under the optimum conditions, which was 5.68% and well matched with the predictive yield.