【作者】 仉燕崃；

【导师】 李楠；

【作者基本信息】 大连理工大学 ， 应用化学， 2006， 硕士

【摘要】 儿茶素是茶叶中主要成分茶多酚的主体(占茶多酚总量的70-80%),由于其具有诸如抗肿瘤、清除自由基、抗心脑血管疾病、防龋等重要的生物活性而日益受到人们的关注。天然存在且含量较多的儿茶素单体有6种,其中以表没食子儿茶素没食子酸酯(EGCG)与表儿茶素没食子酸酯(ECG)两种酯型儿茶素单体药理活性最强,因此需求量较大。 本文以含EGCG 25.5%、ECG 17.3%的茶多酚粗品为原料,以HPD-600型大孔吸附树脂为柱填料,在单因素实验的基础上,采用正交法设计实验,用方差分析优化出了EGCG和ECG在大孔吸附树脂柱上的分离纯化条件为:洗脱流速为1BV/h(BV=床层体积);径高比3∶30;洗脱方式为水、10%、20%、45%乙醇水溶液顺次进行梯度洗脱;洗脱体积4 BV。分别收集不同浓度酒精洗脱液,薄层结果显示10%酒精洗脱液为EGCG组分,45%酒精洗脱液为ECG组分。两洗脱液经旋转蒸发,得到两组分的浓缩液EGCG纯度为66.32%,ECG纯度为79.68%;采用乙酸乙酯萃取工艺进一步纯化,其纯度分别提高到77.71%及82.03%。两单体的制取率分别为EGCG:78.0%;ECG:82.9%。 本研究经过一次柱层析,即可得到高纯的EGCG、ECG产品。采用的分离设备经济、简单,分离工艺操作容易掌握,过程容易控制,方法简便,溶剂安全无毒,单体提取率及产品纯度都很高,分离纯化过程易于工业化。 另外,本文还在实验的基础上,初步探讨了儿茶素在HPD-600型大孔吸附树脂填充的固定床吸附器中的吸附特性,以期为吸附工程设计和吸附操作提供理论参考。实验考察了上样流速及床层高度对吸附穿透时间的影响;并在简化,假设的基础上建立了固定床吸附动力学模型,用此模型回归固定床吸附穿透曲线数据,获得了分离过程的传质模型;还根据物料衡算式推导出了传质区长度的计算公式。更多还原

【Abstract】 Catechins are the primary components of tea polyphenols which are the principle part in the tea leaves(accounting for 70-80%), and are receiving increasingly attention from the scientific rasearchers because of their bioactivities such as anti-tumour, clearance of free radicals, caries-prevention and odour-depression. There are about 6 kinds of catechins monomers , in which epigallocatechin-3-gallate(EGCG) and epicatechin-3-gallate(ECG) have the highest pharma-activity so are in a high demand.In this thesis, tea polyphenols are used as the raw materials, and the macroporous adsorption resin as the column packings. Single factor tests, orthogonal experimental designs and variance analyses are applied to optimize the operation parameters for purifying ester catechins using HPD-600 macroporous adsorption resin. The results indicate that optimum eluting conditions are as follows: eluting rate: lBV/h(BV=bed volume);ratio of diameter to height of the chromatographic column: 3 : 30;eluting mode: water -10% alcohol-20% alcohol-45% alcohol and eluting volume: 4BV. Then effluent fractions are collected according to different ethanol concentrations respectively. Analysis by TLC indicates that EGCG exists in 10% effluent fraction and ECG in 45% effluent fraction. The purities of EGCG and ECG are 66.32% and 79.68% respectively in corresponding condensed parts. Furthermore, ethyl-acetate extraction technique is used to purify the two kind of ester catechin monomers, and the purities are increased to 77.71% and 82.03% respectively. The recoveies of EGCG and ECG are 78.0% and 82.9%.In this work, rather economic equipments have been adopted, and EGCG and ECG products of high content can be obtained by using single chromatographic sepration. The developed technology is simple and easy to control with the advantages of low operation cost, using safe and nonpoisonous solvent and obtaining products of rather high purity. The separation technique is easy to be industrialized.In addition, based on the experimental data, the adsorption characteristics of catechins have been investigated in case of using HPD-600 macroporous adsorption resins that are packed in the fixed bed, so as to provide the bases for engineering design. Influenses of dlution rate and height of bed on breakthrough curve are also studied. An adsorption model for catechins mass transfer through HPD-600 resin is proposed and the height of mass transfer zone and total mass transfer coefficient in different operation conditions are calculated.更多还原