| The experiment aimed to obtain the optimal parameters for extracting polyphenols from corn silk by the ultrasound-deep eutectic solvents (DESs) method and to study the antioxidant activity of the polyphenols from corn silk. Using DESs (with a molar ratio of malic acid to choline chloride of 2:1) as the extraction reagent and based on single-factor experiments, the influences of changes in conditions such as the liquid-to-solid ratio, ultrasonic power, extraction temperature, and extraction time on the yield of polyphenols from corn silk were investigated. The extraction process of polyphenols from corn silk was optimized through response surface experiments, and its performance in scavenging DPPH free radicals and hydroxyl free radicals was analyzed.The results showed that the optimal parameters for extracting polyphenols from corn silk were as follows: a liquid-to-solid ratio of 30:1, an ultrasonic power of 330 W, an extraction temperature of 61 °C, and an extraction time of 70 min. Under these extraction conditions, the yield of polyphenols from corn silk was 11.36 mg/g. When the concentration of the obtained polyphenols from corn silk was 0.30 mg/mL, the scavenging rates of DPPH free radicals and hydroxyl free radicals reached 87.21 % and 92.89 %, respectively. The IC50 values for the scavenging of DPPH free radicals and hydroxyl free radicals by the polyphenols from corn silk were 0.121 mg/mL and 0.127 mg/mL, respectively. The optimized extraction parameters for polyphenols from corn silk are reliable, and the obtained polyphenols from corn silk exhibit very good antioxidant activity and have great potential for the development of natural antioxidants. |
