【作者】 杨解；

【导师】 崔政伟；

【作者基本信息】 江南大学 ， 机械设计及理论， 2009， 硕士

【摘要】 天然植物中含有非常丰富的活性成分,被广泛用于药品、保健品和化妆品中。我国拥有丰富的中药资源,但中药提取物的国际市场占有率还不足5%。由于植物中有效成分的含量相对较少,浸提(提取、浸出或萃取)过程需要耗费大量的溶剂和能量,因此提取是植物药生产中的最重要的工序,直接影响产品的质量、生产成本及原料的利用率等。开发高效节能的提取新技术和提取设备是一个关键点和突破口,对加快中药生产现代化的进程,有效开发和利用中草药资源,有着重要的意义。本研究提出了真空微波预处理的方法,该方法先对干物料进行一定程度的浸润,然后用微波辐射破坏植物细胞结构,之后再采用传统的提取方法。在微波预处理阶段,微波作用于物料内的汽化剂,微波几乎全被物料吸收,处理时间只有两三分钟。本研究采用水做预处理汽化剂,在微波腔内施加真空度,使汽化剂(水)在低温条件下汽化,达到既破坏细胞壁,又保留活性成分的目的,解决了用乙醇等做汽化剂安全性低,成本高的缺点。研究了真空微波预处理对灵芝、竹叶中的有效成分提取率的影响,首先研究了微波预处理辐射过程对植物细胞结构的破坏情况,在扫描电子显微镜下观察,可以发现,微波后的植物细胞结构几乎被完全破坏,微观结构变的疏松,有利于后续提取过程的传质。对微波预处理后灵芝和竹叶中的有效成分——灵芝多糖和竹叶黄酮的提取得率、提取液的浊度和粘度进行测试分析,利用响应面分析法优化出灵芝多糖和竹叶黄酮提取的最佳预处理工艺参数,结果表明本方法与传统水浴提取法相比,不仅可以大量缩短提取时间,还提高了有效成分的提取率。研究了真空微波预处理后后续浸提的动力学及其数学模型。在修正后的Fick扩散第一定律基础上,结合微波场对固液扩散机制的影响,研究了物料在微波预处理后水浴浸提过程中,有效成分浸提过程的动力学方程,并同传统水浴浸提法的动力学方程比较,对强化机理进行了一定的探讨,并用试验数据对该方程进行检验,具有一定的理论参考价值。研究表明真空微波预处理方法能够快速破坏植物细胞壁,使的后续的提取时间大大缩短,得率提高,是一种理想的强化提取方法。更多还原

【Abstract】 Natural plants contain a diverse group of bioactive substances with a broad range of applications in medicine, healthcare product and cosmetic etc. China is rich in medical herb resources, but has a weak market share (less than 5%) on plant extractions in the world. Because effectual compositions of plants were a little and the extraction process needs a lot of solvent and energy, the extraction is the most important unit operation,which affect production quality, cost and utilization ratio of material directly. Therefore, it is important to develop high efficient and energy-saving extract technology and equipment which will lead acceleration the process of modernization of Chinese medicine, exploiting and utilization the resources of herbal medicine in our country in higher efficient.The method of vacuum-microwave pretreatment is proposed and used in current study, the materials were wetted for some time in advance, then were irradiated by vacuum-microwave to destroy cell’s structure of plants, and then the traditional extraction was employed in succession. During the microwave irradiation, microwave energy was nearly all absorbed by the solvents which moved into internal area of cell during wetting and the total irradiation time was about 2-3minutes because the materiels were just wetted by limited solvents. The effectual compositions are retented and the extraction efficieny is higher due to the shorter treatment time, lower pressure and destruction the wall of cell. Furthermore the water was employed as vaporized solvents in current method because vacuum in the microwave cavity was imposed resulting in lower vaporization temperature, it is safer and lower cost than ethanol or other solvents is used.The effects of vacuum-microwave pretreatment on extracting effectual composition from Ganoderma Lucidum and Bamboo leaves were studied. First, the extent of cell-wall breaking by vacuum-microwave irradiation was observed and checked by SEM. The pictures of SEM showed that cell-walls were almost destructed after microwave irradiation. The Ganoderma Lucidum and Bamboo leaves were pretreated by vacuum-microwave in advance, then the conventional water-bath extraction was employ, and the effectual compositions extraxtion rate, turbidity and viscosity of extracts were tested and analyed. The vacuum-microwave irradiation parameters were optimized and confirmed by response surface methodology. Compared with the traditional water-bath method,the results showed that the current method can not only shorten the time of extraction but increase the rate of extraction of effectual compositions.A kinetic mathmatical model for extraction process after vacuum-microwave pretreatment was also studied, which is based on the revised Fick’s first law of diffusion. The experiment datas matched the kinetic equation well. Therefore it provides a theoretical reference for the vacuum-microwave pretreatment extraction of Chinese traditional medicine. The results show that vacuum-microwave pretreatment is a perfect assisted extraction method, which can destruct the cell-wall of plants rapidly, shorten extraction time and increase extraction rate.更多还原