核桃楸叶多酚提取工艺的响应面法优化及其抗氧化性分析

采用核桃楸叶为原料,超声波辅助提取和紫外分光光度计对其多酚类物质进行含量测定。在单因素试验基础上,通过响应面法优化了核桃楸叶多酚类物质的提取工艺,得出核桃楸叶多酚类物质最佳提取条件为:乙醇体积分数70%,液料比15∶1,超声时间30min,超声温度60℃。核桃楸叶多酚类物质对羟基自由基、亚硝酸根离子、超氧阴离子、DPPH自由基有较强的清除能力,其对4种自由基的清除能力强弱顺序为DPPH自由基超氧阴离子羟基自由基亚硝酸根离子,核桃楸叶多酚类物质对4种自由基的清除能力整体强于化学防腐剂苯甲酸,这表明核桃楸叶多酚类物质具有较强的抗氧化活性,是一种天然的抗氧化剂,为下一步研究多酚类物质的抗氧化性提供了依据。

Process Optimization and Antioxidant Activity of Polyphenols Extracted from Leaves of Juglans mandshurica Maxim

Polyphenols were extracted from the leaves of Juglans mandshurica Maxim using an ultrasound-assisted process.Polyphenol content was determined by UV spectrophotometry.The extraction was optimized by a response surface experiment to arrive at the conditions including 70％ by volume of ethanol as solvent,a solvent:solid ratio of 15∶ 1,and an ultrasonic treatment of 30 min at 60℃.The polyphenol extract showed an excellent capacity in scavenging free radicals and ions in the order of DPPH radical ＞ superoxide anion ＞ hydroxyl radical ＞ nitrite ion.It was more powerful than what the chemical preservative,such as benzoic acid,can provide.Thus,the polyphenols extracted from leaves of J.mandshurica by the current method could be a new natural antioxidant for potential applications.