Modeling and optimization of ultrasound-assisted extraction of polysaccharide from Cucurbita moschata

► UAE of polysaccharide from pumpkin. ► Central composite rotatable design was applied to find out the optimum conditions. ► Second order polynomial regression model was fitted to data. ► Optimal conditions were determined by Derringer's desired function methodology. ► Experimental values showed good agreement with the values predicted by the model. Polysaccharides from pumpkin were extracted by ultrasound-assisted extraction technology using four factors at five levels central composite rotatable response surface design (CCRD). On using single factor analysis, process variables such as extraction temperature (50–70°C), power of ultrasound (50–70W), time (15–25min) and solid–liquid ratio (1:10–1:20g/ml) were selected. Experiments were conducted to evaluate the effects of four independent variables on the maximum extraction yield of polysaccharides. From the experimental data, second order polynomial mathematical model were developed with high coefficient of determination values (R2>0.96). From response surface plots, temperature and ultrasound power exhibited independent and interactive effects on the extraction yields. Extraction temperature of 70°C, ultrasound power of 70W, time of 23min and solid–liquid ratio of 1:10g/ml were determined as optimal conditions with a maximum polysaccharides yield of 16.21%, which was confirmed through the validation of the experiments.