Optimization of total polysaccharide extraction from Dioscorea nipponica Makino using response surface methodology and uniform design

On the base of single factor investigation, effects of extraction temperature, extraction time and ratio of water to material as well as their interactions on the yield of total polysaccharide from Dioscorea nipponica Makino were studied by uniform design and response surface methodology, respectively. The optimal process conditions were obtained by response surface methodology as follows: ratio of liquid to solid 33:1, extracting duration 134 min, and extracting temperature 95 °C, under optimized conditions, and the experimental yield 3.82% agreed closely with the predicted yield 3.9%. The tri-dimensional response surfaces were plotted by design-expert, and it was indicated that both extraction temperature and extraction time had interaction effects on the response value and there were no interaction effects of extraction time and liquid:solid ratio. Therefore, the application of response surface methodology in the extraction of total polysaccharide from D. nipponica Makino is more significant than uniform design.