Based on these results and the model equation, it was found out that the optimal combination of the independent variables was ethanol concentration of 63% v/v at 40 C for 10 min, corresponding to the maximal concentration of extracted oligosaccharides in scallion of 7.95 ± 0.135 g/100 g FW. To compare the predicted results with the experimental ones, experimental rechecking was performed using optimal conditions. The good correlation between experimental and predicted values confirmed the adequacy of the response model. A chromatographic profile of oligosaccharides extracted by ultrasound assistance from scallion under optimized conditions is shown in Fig. 3.