【作者】 张恒春；

【导师】 杨俊红；

【作者基本信息】 天津大学 ， 制冷及低温工程， 2007， 硕士

【摘要】 本文选择有代表性的药用植物黄芪、当归为研究对象,以水为提取溶剂,考虑微波特殊的加热特性和复杂的药材形态结构及其提取物组成,结合实验研究和理论分析,考察微波辅助溶剂提取过程中提取物分子量分布、药材微观结构及原子力显微特征的变化,研究生物材料内部纳微尺度的物质传递现象及其规律,探讨微波场强化药用植物提取的传质机理。主要研究内容和结果如下:1.通过比较微波辅助提取和传统回流两种提取工艺下黄芪提取液分子量分布特征及其变化规律,结果表明,对于分子量为2000～50000 Da的较大物质,MAE提取10 min的浸出量是传统回流30 min的16.6倍;对于分子量大于50000 Da的物质,MAE提取10 min的浸出量仅占总浸出物的2.87 %,而传统回流30 min时为7.94 %,说明微波辅助提取工艺在目标成分的快速浸出,尤其是在较大分子量的快速浸出和避免无效物质的浸出方面显著优于传统回流工艺,能够很大程度地缩短提取时间,同时提高目标成分的提取率和纯度,这对于中药现代化研究和开发具有重要的意义。2.对于含有阿魏酸、藁本内酯等热不稳定成分的中药材当归,微波辅助提取工艺也明显优于传统回流。微波15 min提取得到的分子量2000Da以下的物质是传统30 min的2.33倍,分子量100000 Da以下的物质是传统的4.91倍。3.进一步的研究表明,微波提取黄芪有效成分时功率选择应小于400 W,过大的微波功率会使药材发生热凝固,微小导管通道闭塞,不利于有效成份的浸出;微波作用可以使黄芪多糖发生降解,提取物的粒径较小且尺度分布集中,微波工艺提取到的有效成分的粒径分布在3.8500 nm～4.3640 nm之间,而传统提取到的有效成分粒径分布在4.3230 nm～14.8118 nm。另外,对提取工艺进行放大时,应考虑微波穿透深度对提取效果的影响;对黄芪提取液进行干燥操作时,微波工艺具有一定的优越性。更多还原

【Abstract】 In order to discuss mass transfer mechanism on microwave enhancing medicinal materials extraction,choosing representative medicinal plants of astragalus and angelica as matrix, water as solvent, considering microwave special heating characteristics, complex micro structure and the extract components of Chinese medicine, this paper studied the molecule weight distribution characters of water extract, and also further analysed nano and micro dimention fluid flow and mass transfer principles within botanical materials.The main work and results are as follows:1. By compared the distribution characteristics of the molecule weight of astragalus extract by microwave assisted extraction (MAE) with that by traditional refluxing technique, it can be shown that materials with molecule weight 2000～50000 Da by MAE for 10 min is 16.6 times of that traditional reflux technique for 30 min. Materials with molecule weight bigger than 50000 Da is only 2.87 % of total extract by MAE for 10 min, but it is 7.96 % of that by traditional reflux technique for 30 min. Results indicate that MAE technique is more beneficial to the extraction of target component with bigger molecule weight and avoiding the extraction of invalid materials. MAE is also advantaged to shorten extraction time to a large extent and improve the extract ratio, and it has significant meanings to the research and development of Chinese traditional medicine modernization.2. Concerning with medicinal plant angelica, MAE is also superior to the traditional flux technique. By compared with traditional refluxing technique, it can be shown that materials with molecule weight smaller than 2000 Da by MAE for 15 min is 2.33 times of that by tradition reflux technique for 30 min, and materials with molecule weight smaller than 100000 Da by MAE for 15 min is 4.91 times of that by tradition reflux technique for 30 min.3. Further studies indicate that microwave power should be less than 400 W during MAE of astragalus, while too high power could make medicinal materials coagulated with heat, which is not good for the extraction of target components. Microwave irradiation also could make the degradation of astragalus amylase, and result in the smaller granules diameter of target components and its more concentrative distribution. The granules diameter distribution of target components extracted by MAE is between 3.8500 nm～4.3640 nm, but that extracted by traditional refluxing extraction is between 4.3230 nm～14.8118 nm. Moreover, the penetration depth of microwave should be considered in MAE, and microwave drying technique is also a kind of reasonable choose in the dehydration operation of water extract.更多还原