响应面法优化超声辅助提取荠菜多酚工艺及其抗氧活性研究

采用超声辅助提取荠菜多酚,并利用响应面法对多酚的提取工艺进行了优化。在单因素实验的基础上,采用四因素三水平的响应面试验优化设计,考察乙醇浓度、提取时间、提取温度和料液比对荠菜多酚提取量的影响,结果显示最佳提取工艺条件为:乙醇浓度为48%,超声提取时间为27 min,提取温度为57 ℃,料液比为1:33 (g:mL),得到多酚提取量的实验值为28.33 mg/g,与模型预测值(28.35 mg/g)相比,其相对误差为0.07%。通过体外自由基(·OH、O₂^-·和NaNO₂)清除能力和还原能力评价了荠菜多酚的抗氧化性,结果显示荠菜多酚具有一定的自由基清除活性和还原能力,荠菜多酚的自由基(·OH、O₂^-·和NaNO₂)半数抑制浓度(IC₅₀值)分别为(0.17±0.01) mg/mL、(0.08±0.01) mg/mL和(18.9±0.02) μg/mL。结论:荠菜多酚是一种天然的抗氧化活性剂和自由基清除剂。

Optimization of Ultrasonic Assisted Extraction Technology of Polyphenol by Response Surface Methodology from Capsella bursa-pastoris and Its Antioxidant Activity

Polyphenol from Capsella bursa-pastoris was extracted by ultrasonic-assisted, and the extraction process was optimized by response surface methodology. On the basis of single factor experiment, the response surface experiment with four factors and three levels was used to study the effect of ethanol concentration, extraction time, extraction temperature and solid-liquid ratio on the extraction rate of polyphenols. The results showed that the optimal extraction conditions were ethanol concentration of 48%, extraction time of 27 min, extraction temperature of 57℃ and solid-liquid ratio of 1:33 (g:mL), under these conditions, the experimental result was 28.33 mg/g. Compared to the predictive value (28.35 mg/g), the relative error was 0.07%. Comparing with conventional antioxidant ascorbic acid, polyphenols from Capsella bursa-pastoris extraction in vitro could be better removing hydroxyl free radical (·OH), superoxide anion radical (O₂-·), nitrite and reduction ability, and IC₅₀ value of extracted Capsella bursa-pastoris polyphenols was (0.17±0.01) mg/mL, (0.08±0.01) mg/mL and (18.9±0.02) μg/mL, respectively. Conclusion:polyphenols obtained in Capsella bursa-pastoris is a natural antioxidant and free radical scavenger.