Optimization of extraction technology of the Lycium barbarum polysaccharides by Box–Behnken statistical design

The quantitative effects of extraction time, extraction temperature, ratio of water to raw material and number of extraction on yield of Lycium barbarum polysaccharides were investigated using response surface methodology (RSM). The four factors chosen for the present investigation were based on the results of a single-factor test. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods. By solving the regression equation and also by analyzing the response surface contour plots, the optimal polysaccharides extraction conditions were determined: extraction time 5.5 h, extraction temperature 100 °C, ratio of water to raw material 31.2 and number of extraction 5. These predicted values were also verified by validation experiments. At last, four isolated fractions of the L. barbarum polysaccharides were characterized by employing GC.