【作者】 段增宾；

【导师】 杨俊红；

【作者基本信息】 天津大学 ， 热能工程， 2005， 硕士

【摘要】 中草药有效成分提取是中药现代化研究的关键环节,传统提取存在着损失大、周期长、提取率不高等缺点。微波辅助提取是将微波技术和传统提取法结合而形成的一种新方法。本课题从实验和模型角度对微波强化中草药提取的传质机理进行了研究。本文综述了微波辅助提取在实验、机理、模型方面的研究进展; 选用甘草、赤芍、山楂、黄连、丹参、灵芝、槐花常用中草药,利用传统提取(回流、索氏)和微波辅助提取(微波直提、微波-传统提取)不同工艺,进行了正交实验、对比实验和提取动力学实验研究; 针对微波预处理-回流提取工艺,建立了提取动力学方程,结合山楂中芦丁的提取工艺进行方程求解,定量分析了微波功率、微波时间对动力学方程参数的影响,综合探讨了微波强化中草药有效成分提取的作用机理,并进行了仿真实验。正交实验表明,各个实验因素与水平的选择对实验结果有很大影响。对于微波-索氏法,甘草、黄连和赤芍提取的主要影响因素是药材粒度,而山楂和丹参的主要影响因素是提取时间。对比实验表明,微波辅助提取具有提取时间短、提取速率快、温度低、纯度高等优点。如甘草酸微波直提的提取速率是索氏提取的27.7倍,是回流提取的19.4倍。提取动力学实验表明,提取工艺及实验参数水平不同,目标成分提取过程的动态特征不同。建立的微波预处理-回流提取动力学方程,反映了提取过程中溶液主体的浓度随提取时间、液固比、粒度及其它工艺参数的变化规律。结合实验研究、模型计算,对微波强化中草药提取的传质机理的研究表明,低功率区和高功率区微波强化目标成分提取的作用机理有所不同。本文实验条件下,对于山楂芦丁提取,低功率(65W)和高功率(455W)均能达到较好的提取效果; 低功率微波作用主要表现为温升引起的热力作用及非热效应,水分汽化量很少; 高功率微波作用还包括水分强烈汽化所带来的作用。微波技术运用于中草药有效成分的提取,可以强化中草药提取的传质过程,是一种优质高效的提取方法。更多还原

【Abstract】 Extraction of valid components plays an important role in the modernization of Chinese herb industry. Traditional extractions methods have the disadvantages of great loss, long period and low yield, etc. microwave-assisted extraction is the new method of combining microwave technology and traditional extraction methods. This paper has carried out a study on the enhancing mass-transfer mechanism of microwave-assisted extraction of Chinese herbal medicine by experimental researching and mathematical modelling. This paper reviewed the latest development of microwave-assisted extraction in recent years, which could be classified into three aspects such as the experimental methods, mathematical models and the mass-transfer mechanism of extraction. For some Chinese herbs in common use such as Glycyrrhizic, Paeoniae Rubra, Hawthorne, Rhizoma Coptidis, Salviae Miltiorrhizae, Ganoderma and Flos Sophaoae, etc, orthogonal experiments, contrast experiments and extraction dynamics experiments was finished by using different extraction technology including traditional extraction (such as Reflux extraction and Soxhlet extraction) and the microwave-assisted extraction (such as microwave extraction and microwave pretreatment extraction). For the microwave pretreatment-reflux extraction technology, the extraction dynamics equation was put forward and applied to simulating Hawthorne Rutin extraction process. In the end, this paper quantitily analyzed the effect of microwave power and irradiation time on some parameters of extraction dynamics equation, and investigated the enhancing mass-transfer mechanism of microwave-assisted extraction of Chinese herbal medicine. The orthogonal experimental results show that, the experiment factor and its level have closely related to result. For microwave-assisted Soxhlet extraction, under the experimental condition in this paper, the major influencing factor of Glycyrrhizic, Rhizoma Coptidis and Paeoniae Rubra is the particle size, and that of Hawthorne and Salviae Miltiorrhizae is the extraction time. The contrast experimental results show that microwave-assisted extraction has the advantages of shorter extraction time, lower extraction temperature, higher yield, etc. Dynamics experimental results show that, for different extraction methods and experiment parameter level, the dynamic characteristic of objective component extraction process is different. The extraction dynamics equation of microwave-assisted pretreatment reflux extraction has been developed, which indicates that the concentration of solution is the function of extraction time, liquid/solid ratio, particle size and so on. By experimental study and mathematical model calculation, we can draw a conclusion that the influence mechanism of microwave on the extraction is different between low power area and high power area. As for the extraction of Hawthorne Rutin, under the experimental condition in this paper, low power (65W) and the high power (455W) all can achieve the same higher extraction yields; the influence of lower microwave power on extraction chiefly behaves thermal dynamics effects and non thermal effects, with only a small amount vaporization; the influence of higher microwave power on extraction chiefly behaves thermal dynamics effects, non thermal effects and the effect with the result of strong vaporization. Microwave can enhance the mass-transfer mechanism of Chinese herb extraction, which is a kind of high quality and efficiency extraction method.更多还原