百香果皮总黄酮的复合酶辅助超声波提取工艺优化及其抗氧化活性分析

采用复合酶辅助超声波法对百香果皮总黄酮进行提取，以黄酮得率为指标，单因素实验分析复合酶的用量、酶解时间、液料比、超声时间对百香果皮总黄酮提取的影响，响应面试验（Box-Behnken）进一步分析黄酮提取的主要影响因素和最优组合，并通过体外检测对DPPH自由基和羟自由基的清除率及还原力。结果表明:复合酶辅助超声波提取百香果皮总黄酮的最佳工艺条件为纤维素酶与果胶酶复配比例2:1、复合酶的用量4.8%、酶解时间为1 h、乙醇体积分数60%、液料比30:1 mL/g、超声时间41 min，在该条件下，百香果皮的黄酮得率为（2.20%±0.05%），回归模型的实测值与预测值2.24%（<1%）接近，模型可靠，抗氧化活性结果表明，当提取液浓度在0.44 mg/L时，DPPH自由基的清除率为90.8%；当提取液的浓度为44 μg/mL时，羟基自由基的清除率最大，此时清除率为84.1%。通过复合酶辅助超声波提取百香果皮中总黄酮可为百香果皮的资源化利用提供途径。综上所述证明百香果皮总黄酮具有较好的抗氧化性，是一种理想的天然抗氧化剂。

Optimization of Extraction Technology of Total Flavonoids from Passiflora edulis peel by Ultrasonic Assisted with Complex Enzyme and Its Antioxidant Activity

The total flavonoids form Passiflora edulis peel were extracted by compound enzyme assisted ultrasonic method. Taking the yield of flavonoids as the index, the effects of the amount of compound enzyme, enzymatic hydrolysis time, liquid-solid ratio and ultrasonic time on the extraction of total flavonoids from Passiflora edulis peel were analyzed by single factor tests. The main influencing factors and optimal combination of flavonoids extraction were further analyzed by response surface test (Box-Behnken), and the scavenging rate and reducing power of DPPH free radical and hydroxyl free radical were detected in vitro. The results showed that the optimum extraction conditions for ultrasonic extraction of total flavonoids from Passiflora edulis peel assisted by composite enzyme were as follows: The ratio of cellulase to pectinase was 2:1, the dosage of composite enzyme was 4.8%, the enzymolysis time was 1 h, the ethanol concentration was 60%, the liquid-material radio was 30:1 mL/g, and the ultrasonic time was 41 min. Under the optimized conditions, the total flavonoids yield was (2.20%±0.05%), which was similar to the predicted yield 2.24% (<1%) of the regression model. The results of antioxidant activity showed that the scavenging rates of DPPH radical and hydroxyl radical were 90.8% and 84.1% when the concentration of flavonoids from Passiflora edulis peel reached 0.44 mg/mL and 44 μg/mL respectively. The extraction of total flavonoids from Passiflora edulis peel by complex enzyme assisted ultrasound could provide a way for the resource utilization of thyme peel. Based on the above research results, the total flavonoids from Passiflora edulis peel had good antioxidant activity and were an ideal natural antioxidant.