Effect of electrolyzed reduced water on chiral theanine and polyphenols in tea

Pure d/l-theanine enantiomers were synthesized separately, and SEM was used for their crystal-structure observation. The novel enantiomeric separating method by HPLC was established using the chiral selector of β-CD in the mobile phase. Green tea, white tea, oolong tea, black tea and Pu-erh tea were tested for theanine enantiomers by different degrees of fermentation. The significantly higher d-enantiomeric proportion of theanine was found in white tea than the others, which was probably due to its specific processing step of withering. The effect of electrolyzed reduced water (ERW) on enantiomeric theanine and polyphenols in tea was explored. There was no change of theanine, but rather a loss of ECG (epicatechin gallate) and an increasing amount of GA (gallic acid). ERW also reduced tea cream, which contains significant amount of polyphenols, indicating its potential application in the tea-beverage industry.     

茶氨酸对小鼠学习记忆能力的影响

采用跳台法及复杂水迷宫法，观察茶氨酸对小鼠学习记忆能力的影响。结果表明，一定剂量的茶氨酸可缩短正常小鼠在复杂水迷宫内抵达终点的时间，减少错误次数；可延长记忆获得障碍小鼠在跳台中首次错误的出现时间，减少错误次数。结论：茶氨酸具有提高学习和记忆能力的功能。     

Liver Injury-preventive Effect of Tea Theanine in Rats

This study was conducted to isolate the constituent, which had a preventive effect on D-galactosamine-induced rat liver injury, from the 70% ethanol-soluble fraction of Japanese green tea. Theanine (glutamic acid γ-ethylamide) was identified as the active compound, and the liver injury-preventive effect of theanine was dose-dependent. L-Glutamic acid γ-ethyl ester, but not glutamine, also brought about a significantly preventive effect on liver injury when added to the diet at equimolar levels to that of 1% theanine. The results indicate that theanine is one of the effective constituents of Japanese green tea in preventing D-galactosamine-induced liver injury.     

两种高效液相色谱法测定茶叶中茶氨酸含量的比较

选取白茶为原料,比较了2种HPLC方法测定茶叶中茶氨酸含量,即不经衍生的三氟乙酸洗脱法和经邻苯二甲醛(OPA)柱前衍生的国标法(GB/T 23193-2008)在茶氨酸含量测定上的数值差异。结果显示:以Wa-ters AccQ.Tag化学试剂包的测定结果作为参照,三氟乙酸洗脱法测定结果与AccQ-Tag试剂盒法的测定结果比较接近,而GB/T 23193-2008测定结果与AccQ-Tag试剂盒测定结果在5%的显著水平上差异显著。在此基础上,对GB/T 23193-2008法中的OPA衍生化反应时间进行了实验论证,发现在338 nm检测波长下,衍生化产物在衍生后15～20 min内最稳定且具有最大信号响应值。     

Changes in the Composition of Raw Tea Leaves from the Korean Yabukida Plant during High-Temperature Processing to Pan-Fried Kamairi-Cha Green Tea

ABSTRACT:  To develop a better understanding of compositional changes occurring during the production of commercial teas, we determined by high-performance liquid chromatography (HPLC) changes in ingredient levels during each of several manufacturing steps used to produce Kamairi-cha, a premium green tea. Kamairi-cha uses pan-frying instead of the usual blanching technique to inactivate the enzymes responsible for producing traditional black tea. The resulting tea lacks the characteristic bitterness of green tea, producing a green tea that is described as sweet tasting. The processing steps used to produce this pan-fried tea were as follows: 1st roasting, 1st rolling, 2nd roasting, 2nd rolling, 1st firing, and 2nd firing. The results show that during production at temperatures up to 300 °C, raw leaves lost (in percent) 97.3 water, 94 two chlorophylls, 14.3 seven catechins, and 2.75 caffeine. A separate analysis showed that the final product contained 21.67 mg/g dry wt of the biologically active amino acid theanine. The results of this 1st report on changes in individual catechins and other tea ingredients in tea leaves during pan-frying make it possible to select production conditions that maximize levels of beneficial tea ingredients. The possible significance of the results for the human diet is discussed.     

生物合成茶氨酸的研究进展及构建基因工程菌合成茶氨酸的可行性探讨

综述了近年来应用微生物发酵法、茶树细胞培养法生物合成茶氨酸的研究进展 ,讨论了构建基因工程菌生物合成茶氨酸的可行性。     

PEG/（NH_4）_2SO_4双水相萃取分离茶氨酸的研究

采用聚乙二醇（PEG）/（NH4）2SO4双水相体系萃取分离生产茶多酚所得废液中的茶氨酸,考察了PEG分子量与含量、硫酸铵含量、pH、温度、加盐（KCl、KBr、KI）、茶氨酸含量对双水相及萃取分离茶氨酸的影响。结果表明,PEG/（NH4）2SO4双水相萃取分离茶氨酸的适宜条件是：PEG平均分子量为4 000,质量分数为10%,硫酸铵质量分数为15%,pH约为6,30℃。在此条件下,茶氨酸的分配系数K1=0.16,蛋白质的分配系数K2=0.28,糖类的分配系数K3=9.8,茶氨酸在下相的萃取率为89.5%,可以将茶多酚废液中的茶氨酸与糖类及其他有颜色的杂质分开。     

乳牛肝菌液态发酵合成茶氨酸的新方法

通过乳牛肝菌液态发酵实现茶氨酸生物合成的新途径。分别考察碳源、氮源、温度、装液量、转速和起始pH值等液态发酵条件对乳牛肝菌生成茶氨酸的影响。试验结果表明乳牛肝菌合成茶氨酸的最适条件是:葡萄糖30g/L,酵母膏7g/L,培养基装液量60mL,起始pH5.5,于28℃条件下140r/min培养10d。经毛细管电泳分析可获得9.08mg/L的茶氨酸生成量。通过乳牛肝菌液态发酵直接生成茶氨酸,不仅丰富了自然界天然合成茶氨酸的物种资源,而且也为开辟茶氨酸制备新途径奠定了研究基础,具有开发应用前景。     

离子交换法从茶叶中提取茶氨酸

介绍了采用离子交换法从茶叶中提取茶氨酸的生产工艺。通过实验,确定了离子交换过程中的操作条件：用732型强酸性阳离子树脂为吸附剂,吸附平衡时间6h;磷酸盐缓冲液为洗脱液,洗脱液pH7．38,洗脱液流速为0．5～1．0BV／h;试液浓度为5～10mg／mL;在此操作条件下茶氨酸的提取率为67％,产品纯度达到99．41％。