Optimization of Crude Polysaccharides Extraction from Dioscorea esculenta by Response Surface Methodology

In this study, response surface methodology (RSM) was employed to optimize the extraction process of crude polysaccharides from Dioscorea esculenta (lesser yam) performed using water decoction. Response surface methodology, based on a three-level, three-variable central Box–Behnken design (BBD), was employed to obtain the best possible combination of extraction time (X 1: 2.0–3.0 h), extraction pH (X 2: 9–11), and water to the raw material ratio (X 3: 20–30 mL/g) for maximum polysaccharide extraction. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods (ANOVA). The optimum extraction conditions were as follows: extraction time of 2.66 h, extraction pH of 10.07, and the ratio of water to raw material of 26.36 mL/g. Under these conditions, the experimental yield was 4.92 ± 0.037 %, which is well in close agreement with the value predicted by the model 4.96 %.