Jiao Ye, He Jialiang, Li Fengli, Tao Guanjun, Zhang Shuang, Zhang Shikang, Qin Fang, Zeng Maomao, Chen Jie
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China.
Food Chem. 2017 Oct 1;232:683-688. doi: 10.1016/j.foodchem.2017.04.059. Epub 2017 Apr 12.
The levels of N-(carboxymethyl)lysine (CML) and N-(carboxyethyl)lysine (CEL) in 99 tea samples from 14 geographic regions, including 44 green, 7 oolong, 41 black, and 7 dark teas were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CML and CEL contents varied from 11.0 to 1701μg/g tea and 4.6 to 133μg/g tea, respectively. Dark tea presented the highest levels of CML and CEL, whereas green and oolong teas presented the lowest levels. Five kinds of catechins in the tea were also analyzed, and spearman's correlation coefficients showed that all the catechins negatively correlated with CML and CEL. The results suggested that withering, fermentation and pile fermentation may facilitate the formation of CML and CEL. Catechins might inhibit the formation of CML and CEL, but their inhibitory effects may be affected by tea processing. The results of this study are useful for the production of healthier tea.
采用液相色谱-串联质谱法（LC-MS/MS）测定了来自14个地理区域的99份茶叶样品（包括44份绿茶、7份乌龙茶、41份红茶和7份黑茶）中N-（羧甲基）赖氨酸（CML）和N-（羧乙基）赖氨酸（CEL）的含量。CML和CEL的含量分别在11.0至1701μg/g茶叶和4.6至133μg/g茶叶之间。黑茶中CML和CEL的含量最高，而绿茶和乌龙茶中含量最低。还分析了茶叶中的五种儿茶素，斯皮尔曼相关系数表明所有儿茶素与CML和CEL均呈负相关。结果表明，萎凋、发酵和渥堆发酵可能促进CML和CEL的形成。儿茶素可能抑制CML和CEL的形成，但其抑制作用可能受茶叶加工的影响。本研究结果有助于更健康茶叶的生产。
