红枣多酚提取工艺优化、成分及抗氧化活性分析

采用超声辅助提取工艺提取红枣中的多酚化合物，选取甲醇浓度、超声时间、超声温度、料液比进行单因素实验，在此基础上，利用响应面法优化工艺参数，使用高分辨液-质联用仪对红枣多酚成分进行测定，以清除DPPH和超氧阴离子自由基能力评价红枣多酚的抗氧化活性。结果表明，红枣多酚超声辅助提取最佳工艺参数为:甲醇浓度70%，超声时间40 min，超声温度60 ℃，料液比1:40（g/mL），此条件下多酚得率为1.397%±0.08%。利用高分辨液-质联用仪测定红枣多酚中含有19种成分，分为酚酸及其衍生物、黄酮类化合物和三萜类化合物。抗氧化实验结果表明，当红枣多酚浓度为0.3 mg/mL时，其对DPPH自由基清除率最大为77.63%；当浓度为1.0 mg/mL时，红枣多酚对超氧阴离子自由基的清除率最大达82.48%，且随着多酚浓度的增大清除能力接近于V_C。综上，从红枣中提取的多酚化合物具有较强的抗氧化活性，是一种极具开发潜力的天然抗氧化剂。

Optimization of Polyphenol Extraction Process,Analysis of Components and Antioxidant Activity of Jujube

The polyphenol compounds in red jujube were extracted by ultrasonic-assisted extraction process. The methanol concentration, ultrasonic time, ultrasonic temperature and solid-liquid ratio were selected to conduct the single factor experiments. On this basis, the response surface methodology was used to optimize the process parameters, and the high-resolution liquid-mass spectrometer was used to determine the polyphenol components in red jujube to evaluate the antioxidant activity of the polyphenol based on its ability to remove DPPH and superoxide anion radicals. The results showed that, the optimal ultrasonic-assisted extraction conditions were as follows: Methanol concentration 70%, ultrasonic time 40 min, ultrasonic temperature 60℃, solid-liquid ratio 1:40 (g/mL). Under these conditions, the polyphenol yield was 1.397%±0.08%. A high-resolution liquid chromatography-mass spectrometry (HPLC-MS) method was developed for the determination of 19 components in jujube polyphenols, including phenolic acids and their derivatives, flavonoids and triterpenoids. The results of antioxidant experiments showed that the maximum clearance of DPPH was 77.63% when the polyphenol concentration of jujube was 0.3 mg/mL. The maximum clearance of superoxide anion radical was 82.48% when the concentration was 0.8 mg/mL, and with the increasing of polyphenol concentration, the clearance was close to V_C, indicating that the polyphenol compound extracted from jujube had strong antioxidant activity and was a natural antioxidant with great development potential.