Development and Application of a Fast Gas Chromatographic Method Offer New Insights into l -theanine Production Regulation in Camellia sinensis L
| Autor: | Jianan Huang, Tiantian Zhang, Lizheng Xiao, Na Tian, Yiping Luo, Meiyi Gu, Yanni Chen, Jorge F. S. Ferreira, Zhonghua Liu, Xiangqin Zhang, Shuoqian Liu |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Journal of Agricultural and Food Chemistry. 69:11142-11150 |
| ISSN: | 1520-5118 0021-8561 |
| Popis: | Tea is the most consumed beverage worldwide, and l-theanine in tea leaves significantly affects their flavor and market quality. We have developed and validated a fast and reliable gas chromatographic method with flame ionization detection (GC-FID) to quantify l-theanine after its extraction from Camellia sinensis (tea plant) and derivatization. The procedure was completed in 40 min, from extraction to chromatographic analysis, with a recovery rate of more than 93% and allowing a high sample throughput. The GC-FID intraday precision was within 0.57-2.28%, while the interday precision ranged from 1.57 to 13.48%. The intraday accuracy ranged from -6.84 to 5.26%, while the interday accuracy ranged from -1.08 to 3.12%. The limit of detection was 2.28 μg/mL, and the limit of quantification was 6.47 μg/mL. The GC-FID method was validated by high-performance liquid chromatography with UV detection (HPLC-UV) and was used to investigate the biosynthesis and regulation of l-theanine in tea plants. We found that plants fed with ethylamine significantly increased l-theanine concentrations in roots, while exogenous supplementation of glutamic acid, carbamide, and glutamine did not significantly affect the l-theanine level in roots. Our results also indicated that roots were not indispensable for the biosynthesis of l-theanine, which was detected in undifferentiated embryonic calluses in concentrations (g/100 g dry weight) as high as in leaves of whole plants (1.67 and 1.57%, respectively) and without any exogenous theanine precursor supplementation. |
| Databáze: | OpenAIRE |
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