利用亚临界丁烷分离茶树鲜叶中的阿维菌素

Subcritical Butane Extraction for Effective Removal of Abamectin in Fresh Tea Leaves

以茶树鲜叶为原料,利用亚临界丁烷流体分离鲜叶表面残留的阿维菌素。在料溶比为1∶10(m/V)的条件下,利用响应面法(RSM)的Box-Benhnken Design(BBD)设计实验,考察不同温度、时间、分离次数等条件对多酚氧化酶活性的影响,同时分析亚临界丁烷处理对茶树鲜叶生理特性的影响。结果表明,亚临界丁烷流体在保持茶叶物理结构和多酚氧化酶活性基本不变的情况下,可有效分离茶叶中的阿维菌素;通过Design Expert软件分析,得出分离阿维菌素的最优工艺参数为温度45℃,时间30 min,分离次数1次,料液比为1∶10(m/V),分离效率大于91%,多酚氧化酶相对活性为25.73%。通过扫描电镜观察,茶树鲜叶结构在丁烷处理前后无明显变化。本研究结果表明,亚临界丁烷流体可有效分离茶叶中的农药残留,为亚临界流体在去除天然植物农残的应用中提供了实验依据和技术支持。

Subcritical butane technology was employed for the separation of abamectin on the fresh tea leaves surface. Under the conditions of solid-liquid ratio of 1： 10 （ m/ V）, the experiment was designed via the response surface methodology and conducted at different temperature,various separation time and discrepant cycle number. Besides,the activity of the polyphenol oxidase （PPO） relating to the quality of the tea was determined and compared. At the same time, scanning electron microscopy （ SEM） was used to observe the surface structure of fresh tea leaves before and after treatment,and the effect on physiological characteristics of the leaves by subcritical butane treatment was analyzed. The experimental results showed that the subcritical butane extraction could effectively isolate the abamectin,making the physical structure basically remained and the polyphenol oxidase activity preserved as well. Through the analysis by Design Expert software,the optimal processing parameters of separating abamectin were as follows： 45℃,30 min,1 cycle, and solid-liquid ratio of 1：10 （ m/ V）. Under the optimal conditions, the separation efficiency was over 91% and the relative PPO activity was 25. 73%. The structure of fresh tea leaves changed insignificantly before and after the butane processing. This study suggested that the subcritical butane extraction technology could effectively remove pesticide residues in tea,thus provided a certain scientific basis for application of subcritical fluid removal of pesticide residue in natural plants.