Extraction optimization of antioxidant polysaccharides from the fruiting bodies of Chroogomphis rutilus (Schaeff.: Fr.) O.K. Miller by Box-Behnken statistical design

Response surface methodology (RSM) was used to optimize the extraction conditions of polysaccharides (CRP) from the fruiting bodies of Chroogomphis rutilus with a Box-Behnken design (BBD). Three independent variables such as extraction temperature (°C), extraction time (h) and ratio of water to raw material were investigated. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis. The 3-D response surface plot and the contour plot derived from the mathematical models were applied to determine the optimal conditions. The optimum extraction conditions were as follows: extraction temperature 96.6 °C, extraction time 2.7 h and ratio of water to raw material 22. Under these conditions, the experimental value of 57.7 ± 0.77 was well in close agreement with value predicted by the model. Preliminary in vitro antioxidant activity test showed CRP could scavenge hydroxyl radicals in a dose-dependent manner.