| Title: | Formation of Volatile Tea Constituent Indole During the Oolong Tea Manufacturing Process |
| Author(s): | Zeng L; Zhou Y; Gui J; Fu X; Mei X; Zhen Y; Ye T; Du B; Dong F; Watanabe N; Yang Z; |
| Address: | "Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China. University of Chinese Academy of Sciences , No.19A Yuquan Road, Beijing 100049, China. Waters Technologies (Shanghai) Ltd. , No. 1000 Jinhai Road, Shanghai 201203, China. College of Food, South China Agricultural University , Wushan Road, Tianhe District, Guangzhou 510642, China. Juxiangyuan Health Food (Zhongshan) Co.,Ltd. , No. 13, Yandong Second Road, Torch Development Zone, Zhongshan 528400, China. Guangdong Food and Drug Vocational College , Longdongbei Road 321, Tianhe District, Guangzhou 510520, China. Graduate School of Science and Technology, Shizuoka University , 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan" |
| ISSN/ISBN: | 1520-5118 (Electronic) 0021-8561 (Linking) |
| Abstract: | "Indole is a characteristic volatile constituent in oolong tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of oolong tea manufacturing process. However, formation of indole in tea leaves remains unknown. In this study, one tryptophan synthase alpha-subunit (TSA) and three tryptophan synthase beta-subunits (TSBs) from tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of oolong tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in oolong tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black teas contain much less indole, although wounding stress is also involved in the manufacturing process. Stable isotope labeling indicated that tea leaf cell disruption from the rolling process of black tea did not lead to the conversion of indole, but terminated the synthesis of indole. Our study provided evidence concerning formation of indole in tea leaves for the first time" |
| Keywords: | Camellia sinensis/*chemistry/enzymology/genetics Food Handling Indoles/*analysis Plant Leaves/chemistry/enzymology/genetics Plant Proteins/genetics/metabolism Tryptophan Synthase/genetics/metabolism Volatile Organic Compounds/*analysis indole mechanical d; |
| Notes: | "MedlineZeng, Lanting Zhou, Ying Gui, Jiadong Fu, Xiumin Mei, Xin Zhen, Yunpeng Ye, Tingxiang Du, Bing Dong, Fang Watanabe, Naoharu Yang, Ziyin eng 2016/06/07 J Agric Food Chem. 2016 Jun 22; 64(24):5011-9. doi: 10.1021/acs.jafc.6b01742. Epub 2016 Jun 13" |
