微波超声协同提取白刺果原花青素工艺及抗氧化性研究

本实验以白刺果为原料，采用单因素结合响应面法对微波超声协同提取白刺果原花青素工艺进行优化，并以DPPH自由基清除率、ABTS自由基清除率、羟自由基和总还原能力评价其抗氧化活性。结果表明，乙醇浓度、液料比、微波时间和超声温度对白刺果原花青素得率的影响明显，优化后的工艺条件为乙醇浓度65%，液料比14.5 mL/g，微波时间2 min，超声温度50 ℃，白刺果原花青素得率平均值为（17.289±0.402）mg/g，与理论预测值相差2.4%，说明由该模型优化的最佳提取工艺条件稳定可靠，具有实际应用价值。利用大孔树脂对提取物进行纯化后的纯度达到81.4%。体外抗氧化试验结果表明，白刺果原花青素不仅具有良好的还原能力，对ABTS自由基和DPPH自由基均具有较强的清除能力，IC₅₀分别为0.261 mg/mL和0.159 mg/mL，对羟自由基也具有一定的清除能力，IC₅₀为0.712 mg/mL。因此，微波超声协同能够明显地提高提取效率，且白刺果原花青素具有较强的体外抗氧化活性，为全方位利用白刺资源提供科学参考。

Microwave-Ultrasonic Extraction of Proanthocyanidins from Nitraria and Its Antioxidant Analysis

The single-factor combined response surface method was used to optimize the microwave-ultrasonic extraction of Nitraria tangutorum proanthocyanidins, and their antioxidant activity was evaluated by assessing ABTS and DPPH free radical scavenging capacity and total reduction ability. The results showed that the liquid–material ratio, ethanol concentration, microwave time and ultrasonic temperature had significant effects on the extraction rate of proanthocyanidins. The optimal extraction conditions were as follows: ethanol concentration of 65%, liquid-material ratio of 14.5 mL/g, microwave time of 2 min, and ultrasonic temperature of 50 ℃. The average extraction rate of proanthocyanidins from Nitraria tangutorum was (17.289±0.402) mg/g, with only a 2.4% difference from the theoretical prediction, indicating that the optimal extraction conditions optimized by the model were stable and reliable and had practical application value. The purity of the extract after purification with macroporous resin reached 81.4%. The results of in vitro antioxidant experiments showed that the proanthocyanidins of Nitraria tangutorum had suitable ABTS (IC₅₀=0.261 mg/mL) and DPPH (IC₅₀=0.159 mg/mL) free radical strong scavenging capacity, it also had a certain ability to scavenging hydroxyl radicals (IC₅₀=0.712 mg/mL), with good reduction ability. Therefore, microwave-ultrasonic combine can improve the extraction efficiency significantly, and Nitraria tangutorum proanthocyanidins has strong anti-oxidative activity in vitro. It provides a scientific reference for the comprehensive utilization of Nitraria.