Optimization of extraction conditions of Opuntia dillenii Haw.polysaccharides by response surface analysis and their antioxidant activity study

This study examined the extraction conditions of Opuntia dillenii Haw. Polysaccharides(ODPs) with a series of methods. Firstly,based on the single-factor tests,response surface methodology was used to investigate the effect of three parameters(liquid-materal ratio,extraction time,exraction temperature) on the ODPs yields.Secondly,a second-order polynomial regression model was established using a Box-Behnken experimental design. Finally,the DPPH· scavenging and protein content of ODPs was measured. Consequently,the exraction temperature,liquid-material ratio,extraction time were the major factor affecting the exraction rate of ODPs with a very low p-values(p<0.001). The polysaccharides and protein content of ODPs and the DPPH· scavenging of ODPs were the highest under the 95℃ extraction temperature. The optimal conditions exhibited a liquid-materal ratio 62 ∶1,extraction time 3.5h and exraction temperature 93℃. Under these conditions,the actual extraction rate of ODPs was 25.05%, while the predicted value was 25.14%. In conclusion, the conditions optimization by the response surface method were better for enhanced the extraction rate,and the exraction temperature of 95℃ was better for the antioxidant activity of ODPs.