低共熔溶剂微波辅助萃取油樟精油及抗氧化特性分析

Study on the Microwave-Assisted Extraction of Essential Oil from Cinnamomum longipaniculatum with Deep Eutectic Solvents

摘要: 本研究采用低共熔溶剂微波辅助蒸馏法获得油樟精油，在传统水蒸气蒸馏的溶剂水中加入了由氯化胆碱和1,4-丁二醇熔融制成的低共熔盐，通过优化氢键受体与氢键供体的摩尔比，得到低共熔盐的最佳配比(氯化胆碱与1,4-丁二醇的摩尔比为1:5)；通过优化低共熔盐与水的体积比(低共熔盐与水的体积比为5:5)，得到水蒸气蒸馏的最佳溶剂。然后通过单因素试验及响应面优化微波辅助蒸馏的过程参数为：微波功率700 W，操作温度120℃，微波时间20 min。所得油樟精油萃取量为25.0 mL/Kg，在同样的微波辅助萃取条件下，水蒸气蒸馏所得精油萃取量为21.3 mL/Kg。对微波时间、微波功率、微波温度、料液比进行响应面优化实验，利用多元线性回归方程进行数据分析，可知微波时间与微波功率具有较强的交互作用。利用GC-MS分析精油的成分，并与水蒸气蒸馏、微波水蒸汽蒸馏精油得分成分做出对比。在DPPH阴离子、ABTS阳离子自由基清除实验中，50%浓度的精油对DPPH阴离子清除率为55.47%，5%浓度的精油对ABTS阳离子清除率为98.78%。可见，油樟精油对两种自由基具有较高的清除率，且对ABTS阳离子的清除能力远高于DPPH阴离子。

Abstract: In this study, essential oil of Cinnamomum longepaniculatum was obtained by microwave assisted distillation with deep eutectic solvent (DES). Eutectic salt made by melting 1,4-butanediol and choline chloride was added into the solvent water of traditional steam distillation. The molar ratio of hydrogen bond acceptor and hydrogen bond donor was optimized; the optimum proportion of eutectic salt was obtained (the molar ratio of choline chloride to 1,4-butanediol is 1:5); the volume ratio of eutectic salt to water was optimized (the volume ratio of eutectic solvent to water is 5:5), the best solvent was obtained by steam distillation. The process parameters of microwave assisted distillation were optimized by single factor test and response surface. The results showed that microwave power is 700 W; the operating temperature is 120˚C; microwave time is 20 min. The extraction yield of essential oil from Cinnamomum longepaniculatum is 25.0 mL/Kg. Under the same microwave-assisted extraction conditions, the amount of essential oil extracted by steam distillation is 21.3 mL/Kg. The response surface optimization experiment was carried out for the solid-liquid ratio at microwave time, microwave power and microwave temperature, in which multi linearity regress mechanic to analyze data is used. It is known that microwave time and microwave power have a strong interaction. GC-MS was used to analyze the components of essential oils, and the results were compared with that of microwave steam distillation. The DPPH and ABTS free radical scavenging experiments showed that the DPPH anion scavenging rate of 50% essential oil was 55.47% and the ABTS cation scavenging rate was 98.78%. As a result, Camphor oil has high scavenging rate of two free radicals, and the clearance ability of ABTS is much higher than that of DPPH.