Effect of electrolyzed reduced water on chiral theanine and polyphenols in tea
- 作者：Yusheng Zhao ; Ping Li ; liping01@tongji.edu.cn ; Ling Ge ; Yan Wang ; Ting Mo ; Xinping Zeng ; Xiaodan Wang
- 关键词：Tea ; Chiral theanine ; Polyphenol ; Electrolyzed reduced water
- 刊名：Food Chemistry
- 出版年：2012
- 期刊代码：48_03088146
- 类别：abs
- 出版时间：15 October, 2012
- 卷：134
- 期：4
- 页码：1761-1766
- 文件大小：780 K
摘要
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 尾-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.