响应面法优化黑化红枣三萜酸提取工艺及抗氧化活性研究

目的:以黑化后的红枣为试材，研究其三萜酸提取工艺条件及抗氧化活性。方法:通过单因素实验和Box-Behnken响应面试验进行超声波提取黑化红枣三萜酸工艺优化，并测定黑化红枣三萜酸纯化前后对DPPH、ABTS自由基的清除能力和总还原力以评估其体外抗氧化活性。结果:黑化红枣中三萜酸的最优提取工艺参数为:50%乙醇浓度，液料比23:1 mL/g，超声时间30 min，超声功率300 W，在此条件下，三萜酸含量为1.313±0.01 mg/g；黑化红枣三萜酸粗提物和纯化物清除DPPH、ABTS自由基的半抑制浓度（IC₅₀）分别为0.571、0.053和0.186、0.059 mg/mL，总还原力则与样品浓度呈现一定的量效关系。结论:该工艺简单、合理可行，黑化红枣三萜酸具有良好的抗氧化活性。

Optimization of Extraction and Antioxidant Activities of Triterpenic Acids from Blacked Jujube by Response Surface Methodology

Objective: Blacked jujube was used as raw materials to study the extraction conditions and antioxidant activity of triterpenic acids. Methods: The ultrasonic extraction process of triterpenic acids from blacked jujube was optimized by single factor and Box-Behnken response surface experiments. The antioxidant activity of before and after purification of triterpenic acids were evaluated by determining the scavenging capacity of DPPH and ABTS+ free radicals and total reducing power. Results: The optimum extraction parameters were as follows: 50% ethanol concentration, liquid-solid ratio 23:1 mL/g, ultrasonic time 30 min, ultrasonic power 300 W. Under these conditions, the yield of triterpenoid acids was 1.313±0.01 mg/g. The half inhibitory concentration (IC₅₀) for scavenging of DPPH· and ABTS+· of crude and purified triterpenoid acids from blacked jujube were 0.571, 0.053, 0.186 and 0.059 mg/mL, respectively. The total reducing power showed a certain dose effect relationship with the sample concentration. Conclusions: The process was simple, reasonable and feasible. The triterpenic acids of blacked jujube would have a good antioxidant activity.