Optimization of Ultrasonic-Assisted Extraction of Blackcurrant Polyphenols by Response Surface Methodology and Its Antioxidant Activity

In order to improve the extraction efficiency of blackcurrant polyphenols, ethanol solution was used as extraction solvent, and the polyphenols in blackcurrant fruit were extracted by ultrasonic-assisted method. The effects of ethanol concentration, ultrasonic power, extraction time and solid-liquid ratio on polyphenol extraction from blackcurrant fruit were investigated by single factor experiments. On the basis of single factor experiment, the extraction process was optimized by response surface methodology, and the antioxidant activity of blackcurrant polyphenols was analyzed. The results showed that the optimum extraction conditions of polyphenols from blackcurrant fruit by response surface methodology were as follows: Ethanol concentration was 50%, ultrasonic power was 300 W, extraction time was 20 min, and solid-liquid ratio was 1:10 g/mL. Under the above extraction conditions, the extraction amount of blackcurrant polyphenols was 538.00 mg/100 g. The antioxidant activity showed that the IC₅₀ values of blackcurrant polyphenols on DPPH, hydroxyl and ABTS⁺ radical scavenging rates were 7.97, 7.92 and 5.26 mg/mL, respectively, it indicated that blackcurrant polyphenols had good antioxidant activity. The results could provide reference for industrial production of blackcurrant polyphenols.