Optimization of Ultrasonic-assisted Extraction of Phenolic Compounds from Chinese Quince (Chaenomeles sinensis) by Response Surface Methodology

Functional phenolic compounds were extracted from Chinese quince using highly efficient ultrasonic-assisted extraction (UAE) technology. The experiment was carried out in accordance with a small central composite design (SCCD) five-level and three-variable approach. The optimum combination of solvent concentration, extraction temperature and time with the application of ultrasonic, for the maximum extraction of phenolic compounds from Chinese quince, was obtained by response surface methodology. Responses of phenolic compounds such as total phenolics, total flavonoids, and total flavan-3-ols were determined by the spectrophotometer assay. High significance of each response revealed that this SCCD model well-fitted the experimental parameters as well as the reliability of the predicted value. The optimal UAE conditions obtained by superimposed contour plot were 50% ethanol concentration, 63.9 degrees C extraction temperature, and extraction time 11.4 min. Under the above-mentioned conditions, the experimental results for three responses were total phenolic content 2367.16 mg gallic acid equivalents /100 g, total flavonoid content 544.12 mg rutin equivalents /100 g, and total flavan-3-ols content 709.07 mg catechin equivalents /100 g, which well-matched with the predicted values. The optimal conditions attained from the present study would provide scientific references to economical production of relative phenolic compounds products.