Extraction of Quercetin from Avocado Meal and Its Antioxidant Activity

Abstract

Response surface methodology (RSM) was used to optimize the extraction process of quercetin from pear meal and to investigate its antioxidant capacity. The solvent ratio, ultrasonic power and extraction time were taken as independent variables, and the percentage of quercetin was taken as dependent variable. Through multiple linear regression and binomial fitting of each level of independent variable, the better extraction process was selected by response surface methodology and predicted and analyzed. The antioxidant activity of quercetin was evaluated by scavenging 1.1-diphenylpicrylphenylhydrazine free radical (DPPH.) and reducing ability of iron ions (FRAP). The optimum extraction process was obtained as follows: the ratio of liquid to material was 35 mL/g, the ultrasonic power was 550 W, and the extraction time was 30 min. The content of quercetin was 1.585%. Quercetin in avocado meal has strong DPPH scavenging and iron ion reduction ability. When the concentration is 30 mg/mL, DPPH scavenging rate reaches 70%, and iron ion reduction ability almost equals 6 mmol/L FeSO4 concentration, and has a dose-effect relationship.