荔枝壳多酚提取工艺的响应面法优化及自由基清除活性研究

Studies on Optimization of Technology for Extraction of Litchi Pericarp Polyphenols by Response Surface Method and Their Free-radical Scavenging Activity

为优化荔枝壳多酚提取工艺,在单因素试验的基础上,采用响应面法建立荔枝壳多酚提取方法的二次多项数学模型,同时测定其抗氧化性能。所得最佳提取条件是:液料比13∶1,浸提体积分数64%,浸提时间78min。在此条件下荔枝壳多酚提取率为(5.92±0.04)%(N=3),与理论值(6.04%)相近,说明该二次多项数学模型可靠。荔枝壳多酚对DPPH自由基、超氧阴离子自由基和羟自由基的清除作用均呈一定的量效关系,其半抑制浓度分别为7.36、16.09和65.20 mg/L,表明荔枝壳多酚具有较强的自由基清除活性。

The purpose of the research was to determine the optimum technology and conditions of litchi pericarp polyphenols extraction by using the response surface method（RSM） based on single factor experiment. At the same time, determined the antioxidant activity of the extracts. A second order quadratic mathematical model for litchi pericarp polyphenols extraction was established and the best technical conditions was obtained as follows： ratio of liquid to mate- rial 13：1, extracting concentration 64% and extracting times 78 rain. Under the conditions, the extraction rate of litchi pericarp polyphenols was （5.92±0.04）%（N=3） attained through the verification test, and it was closed to the estimatedvalue 6.04%, which had revealed the validity of the second order quadratic mathematical model. Litchi pericarp polyphenols exhibited a dose-dependent scavenging activity against α,α-diphenyl-β-picrylhydrazyl （DPPH） radicals, superoxide anions and hydroxyl radicals, and the hemi-inhibiting concentration for them was 7.36 mg/L, 16.09 mg/L and 65.20 mg/L respectively, which suggested that litchi pericarp polyphenols had more powerful free-radical scavenging activity.