Application of response surface methodology for optimization of polysaccharides production parameters from the roots of Codonopsis pilosula by a central composite design

Response surface methodology (RSM) was used to optimize the extraction conditions of polysaccharides from the roots of Codonopsis pilosula. A central composite design (CCD) was used for experimental design and analysis of the results to obtain the optimal processing parameters. Four independent variables such as extraction temperature (°C), ratio of water to raw material, extraction time (h), and number of extraction (n) were investigated. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods. The 3-D response surface and the contour plots derived from the mathematical models were applied to determine the optimal conditions. The optimum extraction conditions were as follows: extraction temperature 94 °C, ratio of water to raw material 9, extraction time 2.5 h, and number of extraction 5. Under these conditions, the experimental percentage value was 15.2 ± 0.28, which is well in close agreement with value predicted by the model.