茶多酚

一．根据茶水中茶多酚的含量，定量加入可溶性钙盐，茶多酚与钙盐的摩尔比为1∶(1.05～2)，以烧碱溶液控制茶水pH值为7.5～8.5并使茶多酚沉淀，真空抽滤后的滤饼经36％盐酸酸解，以醋酸酯类有机溶剂萃取后，萃取液经真空干燥，能得到咖啡因含量在3％以下的高纯度茶多酚。

二.一．理化性质以及药理作应：【药物名称】茶多酚(Tea Polyphones，简称TP)【主要成分】儿茶素【化学名】 3，3’，4’，5，7一五羟基黄脘儿茶酚【分子式】C15H14O6【分子量】290【药物类别】新型的天然食品抗氧剂【药物别名】茶单宁、茶鞣酸、茶鞣质【理化性质】在潮湿的空气中易氧化而呈淡黄色至褐色；易溶于水、乙醇、甲醇、乙酸乙酯和丙酮，不溶于氯仿、正丁醇，对热、酸较稳定；在160度的油脂中30分钟仅降解20%，在PH2~7时十分稳定，但当PH》=8或在光照下易氧化而褐变。

【药理作用】抗氧化，清除自由基，诱导肿瘤细胞凋亡【适应症】降压、降血脂、抗突变、防治心血管疾病、抗菌消炎、清除自由基、防癌、抗癌及抗衰老等。

二．茶多酚提取文献小结：在茶叶中提取茶多酚的工艺主要有以下的几种方法：1. 传统工艺：以水或乙醇为溶剂，采用水浴加热至80℃ 保温提取多次。

合并提取液后用等体积的氯仿萃取，分出氯仿相后改用乙酸乙酯多次萃取，将乙酸乙酯大部回收后浓缩近干，冷冻干燥后用去离子水反复重结晶即得精品。

但该法的缺点是操作费时麻烦、溶剂消耗量大、毒性大、成本高、提取率低，在高温下提取，茶多酚易氧化变质等。

2.用微波辐射萃取茶多酚：提取溶剂为50％乙醇，功率320瓦，萃取时间18秒，液固比(mL／g)1：9，二级提取，此条件下的茶多酚的提取率为92．7％。

与传统的索氏提取相比，微波法提取的最大优点是提取时间大大缩短，且提取率较高。

而与超临界二氧化碳萃取相比，它成本低，投资少，提取效率高。

但不适合在实验室操作。

三.现根据参考文献及相关数据，得本实验方案：1.实验原理：利用茶多酚易溶于乙醇、乙酸乙酯，而不溶于氯仿的性质来提取茶多酚。

2.实验器材与试剂：器材：250ml的三口烧瓶，布袋，蒸发皿，分液漏斗，等；试剂：茶叶，碳酸钠，乙醇，氯仿，乙酸乙酯，蒸馏水，等。

3.实验步骤：a)提取：将粉碎的10 g茶叶中加入2g碳酸钠并放入布袋内放好，置于三口烧瓶内，加乙醇50ml，加热煮沸0.5h，倾出提取液至蒸发皿内，再用10ml乙醇洗涤茶叶包，洗涤液并入提取液。

b)分离纯化：将装有提取液的蒸发皿置于石棉网上加热浓缩至提取液体积月约20ml，冷却至室温后将浓缩液移置分液漏斗，加入等量的氯仿萃取2次（萃取时振荡要轻，防止乳化），水层用于制备茶多酚。

将氯仿萃取后的水层用等量乙酸乙酯萃取2次，每次20min，合并乙酸乙酯萃取液，水浴减压蒸馏（或旋转蒸发仪）回收乙酸乙酯，趁热将残液移入洁净干燥好的蒸发皿，改用水蒸气浴加热浓缩至近干，冷却至室温后，放入冰箱内冷冻干燥，将白色粉末茶多酚粗品，粗品用蒸馏水进行重结晶，得茶多酚精品。

干燥后称量，计算产率。

三．2.1 有机溶剂萃取法［6，9，10］溶剂萃取法提取茶多酚的工艺流程见图1。

首先将绿茶叶(或茶叶末)用热水或85%乙醇溶液浸提3次，合并滤液。

滤液经真空浓缩，所得的浓缩液用氯仿萃取，脱除其中的咖啡碱和色素等，进而回收咖啡碱。

水层用乙酸乙酯进行萃取，得到含有茶多酚的乙酸乙酯溶液。

经真空浓缩、干燥，得到茶多酚粗品，并回收乙酸乙酯溶剂。

粗茶多酚经过凝胶柱层析等精制提纯，得到茶多酚精品。

该法工艺技术比较简单，对TP的提取率为10%～15%。

但是有机溶剂用量多。

溶剂回收设备及所消耗的能量比较大。

图1 有机溶剂萃取法提取茶多酚工艺流程2.2 离子沉淀提取法［11～13］离子沉淀法提取茶多酚的工艺流程如图2。

将绿茶叶(或茶叶末)用热水或乙醇溶液浸提，过滤。

在滤液中加入沉淀剂使TP沉淀。

不同沉淀剂使TP沉淀完全的最低pH值和TP的提取率见表1［13］。

过滤，滤液用于提取咖啡碱。

沉淀用稀H2SO4转溶，转溶液用乙酸乙酯萃取，得到含TP的乙酸乙酯溶液。

经真空浓缩干燥得到茶多酚。

该法的特点是减少了有机溶剂的使用量，所得产品中茶多酚含量较高，可达95%以上［11，13］。

但是工艺操作控制比较严格，废渣、废液处理量较大。

表1 不同沉淀剂的提取率和沉淀最低pH值注：表中数据为10次结果的平均值。

图2 离子沉淀提取茶多酚工艺流程2.3 吸附分离提取法［7，14］吸附分离法提取茶多酚的工艺流程见图3。

将绿茶叶(或茶叶末)加热水浸提3次，合并提取液。

茶叶提取液通过高分子吸附剂进行吸附，然后用90%乙醇溶液洗脱，使吸附剂上吸附的TP脱附于乙醇中，经减压蒸馏回收乙醇。

浓缩液经真空干燥或喷雾干燥得到茶多酚。

该法工艺技术简单，能耗低，但需要对TP选择性强的高吸附量的吸附剂。

此外，还有低温纯化酶提取法［7］，盐析法［15］等。

四．一种茶多酚的提取方法，其特征是：将茶叶经开水浸提，滤去茶渣后，制得茶水，根据茶水中茶多酚的含量，在常温下定量加入可溶性钙盐，茶多酚与钙盐的摩尔比为1：（1．05～2），以烧碱溶液控制茶水pH值为7．5～8．5，使茶多酚沉淀，经真空抽滤后制成的滤饼经36％盐酸酸解置换，以低沸点的醋酸酯类有机溶剂萃取后，萃取液经真空干燥，能得到咖啡因含量在3％以下，茶多酚含量95％以上的高纯度茶多酚。

作者：李昂罗一帆陈剑经2005-5-12摘要: 关键词茶多酚提取法沉淀法The research on the extracting method of tea polyphenols from teaLi Ang，Luo Yifan，Chen JianjingClass1，Grade2000，Department of Clinical Medicine，Zho ngshan Medical College Zhongshan Univ ersity，Guangzhou510080。

【Abstract】Objective To st udy the extracting method o【摘要】目的探讨提取绿茶内含有的茶多酚的方法。

方法采用溶剂萃取法与金属盐沉淀法提取绿茶中的茶多酚，讨论两种方法的影响因素和改进条件，同时就两种方法的优劣进行了分析。

结果用改善茶多酚的提取方法提供了茶的实验的基础。

结论不断改进的金属盐沉淀法是高效提取绿茶中茶多酚的有效方法。

关键词茶多酚提取法沉淀法The research on the extracting method of tea polyphenols from teaLi Ang，Luo Yifan，Chen JianjingCl ass1，Grade2000，Department of Clinical Medicine，Zhongshan Medical Co llege Zhongshan Univ ersity，Guangzhou510080.【Abstract】Objective To study the extracting method of tea polyphenols from gree n tea.Methods The orˉganic resolvents and metal salts were used.The affecting factors and improving conditions of the two methods were disˉcussed.Results The results of tw o methods supply an experimental basis for the promotion ofextraction of tea polypheno ls.Conclusion The tea polyphenols extraction with metal salts as precipitator is quite pro mising.Key words tea polyphenols extracting method precipitating method Tea is rich in a kind of polyhydroxyl mass，i.e.tea polyphenols（TP），which is mainly composed of cat echins（weighed as much as79%of TP）.It can greatly efficaˉciously resist to cancer，caducity，radiationand free radiˉcals da mage，and to lower down blood sugar and blood lipid.To extract TP better，in this experiment，organic resolvents and metal salts were used respectively，and by virtue of co mparison between these two methods，a better way could be found.1 Experiment and materials1.1 Materials and Appliance Green tea（provided by the tea graduate school of Gua ngdong agricultural acadeˉmy of sciences），constant temperature heat booster，conˉsta nt temperature drier，instruments for filtration and exˉtraction.1.2 Reagents Fe C 4H 4O 6 solution，the buffer phosˉphate solution（pH7.5），alco hol chloroform（AR），CH 3COOC 2H 5（AR），Na HCO 3 ，Zn Cl2（AR），Al 2（S O 4）3·18H2O（AR），HCl.1.3 Organic resolvents extracting methods to extract The National Major Foundation of China“973”（No:G1998051201），The Scientific Technology Foundation of Guangdon g Province（No:2KB01202S）Luo Yifan，E-mail:xuxuan@ tea polyphenols Thi s method was based on the theory that TP was well soluble in water，alcohol，CH 3C OOC 2H 5，etc.Therefore，we could use water or alˉcohol to extract TP from tea，an d CH 3COOC 2H 5could be used for further extraction form aquatic layer.Reclaiming CH 2COOC 2H 5and solid TP could be produced.The conˉcrete course was as follow ing figure1.1.4 Metal salts precipitating method to extract TP This method was based on the t heory that TP was well soluble in water and could react with a certain kindsof metal s alts to produce deposits at the specific pH values so that TP could be separated from other ed hydrochloric acid to dissolve deposits then extractˉed TP with h elp of CH3COOC2H 5to get solid TP.The concrete course was as following figure2.1.5 The estimation of content of TP Accurately weighed0.1g of TP powder we had just produced，then added water to dissolve it completely and added again to100ml.Acc urately imbibed1.00ml of the above soluˉtion，replaced it to a25ml volumetric flask and added water for4ml，the FeC 4H 4O 6solution for5ml，the added the very buffer solut ion to the ing purified water to make a blank comparison.At the condition that t he colorimetric utensil had a breadth of1cm，and the waveˉlength was540nm，then usedphotometer to calculate its absorbence to estimate the content of TP.Fig.1the flow cha rt for organic resolvents extracting methods to extract tea polyphenolsFig.2 the flow chart for metal salts precipitating method to extract TP2Discussion2.1 The organic resolvents extracting methods （1）The experiment showed that the extractive productive rate was increased with the elevation of the extractive temperatur e.The aquatic circumfluence with a temperaˉture between90℃to95℃was used，the quant ity of tea:alcohol=1:7.5，with a time of1.5h，which would increase the extractive producti ve rate of both TP and caffeine.（2）Alcohol was superior to water in extracting TP if a lcohol was used to soak out TP.（3）The comparaˉtive experiments showed that CH 3 COOC 2H 5was the ideal organic resolvent to extract TP.CH 3COOC 2H 5had a st rong effect on extracting TP selectively，and the initial eradication of impurity was satisf ying.It was proper to select CH 3COOC 2H 5as the extractive resolvent.2.2 The metal salts precipitating method Tea polyphenols can react with manykinds of metallic ions.And the combination is precipitated，which makes good separation bet ween tea polyphenols and other ingrediˉents.At the same condition，the extraltive efficien cy of tea polyphenols is:Al 3+>Zn 2+>Fe 3+>Mg2+>Ba2+>Ca2+ .The quantity of the metal salts was proper.TP are relatively stable when the pH value is between2to7.In thi s experiment，Zn 2+（pH≈5.6）are selected to reassure that the final production we got remains non-oxidized.We have tried several reagents to adjust pH value of thesolutio n，the result is as follows:NaHCO 3>Na 2CO3>NH 3·H 2O>NaOH.NaHCO 3can rea ct with both acid and alkali，the pH value of its aquatic solution is nearly8.6.So it’s unli kely to make the local of the solution oxidized due to alkalinity.2.3 The result analysis From table1，the results show that TP produced by metal s alts precipitating method had a better color and luster as well as less imˉpurity than tho se of organic resolvents extracting method.Meanwhile the extractive productive rate of t he former was higher than that of the latter.Notwithstanding the purity is converse，but we think that tea polyphenols extraction with metal salts as precipitator is quite promisi ng.The method is still further improved.Tab.1 The results from two methods to extract T P method Cr ude productioncolor weight（g）crude productiverate（%）Pure rate（%）final productive rate （%）Organic resolventsextracting method Yellow andgreen powder5.9953 2.99 81.3 2.43 Metal saltsprecipitating method Brown powder 8.1875 8.19 75.26.16（PS:crude productive rate=crude production weight/tea weight;final productive rate=c rude production weight ˇ pure rate/tea weight）参考文献六．1茶多酚的物理性质茶多酚在常温下呈浅黄或浅绿色粉末，易溶于温水(40℃一80℃)和含水乙醇中；稳定性极强，在PH值4—8、250℃左右的环境中，1.5个小时内均能保持稳定，在三价铁离子下易分解。