| Title: | "Contribution of l-theanine to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea during manufacturing processes" |
| Author(s): | Guo X; Song C; Ho CT; Wan X; |
| Address: | "State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China; International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China. State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China; International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China. Electronic address: sckfriend@163.com. International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China; Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA. State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China; International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, People's Republic of China. Electronic address: xcwan@ahau.edu.cn" |
| DOI: | 10.1016/j.foodchem.2018.04.117 |
| ISSN/ISBN: | 1873-7072 (Electronic) 0308-8146 (Linking) |
| Abstract: | "l-Theanine, the most abundant amino acid in tea, is widely believed to be associated with the tea taste, however, its contribution to the formation of tea aroma is still unknown. Volatiles were determined and nitrogen-containing compounds formed during manufacturing processes were quantified. Lower levels of total sugar and l-theanine were detected in the Oolong tea product undergoing full fire processing (FFOT) suggesting that l-theanine probably involved in the volatile formation during manufacturing processes. Methylpyrazine and 2,5-dimethylpyrazine, two newly formed compounds in FFOT, together with other volatiles were successfully detected in a model thermal reaction of d-glucose and l-theanine (GT-MTR) but not detectable in thermal reactions with single d-glucose (G-MTR) or l-theanine (T-MTR). The concentration of 2,5-dimethylpyrazine increased significantly by adding additional l-theanine to 2nd roasted tea. Our study demonstrated that l-theanine, at least partly, contributed to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea" |
| Keywords: | Flavoring Agents/analysis Food Handling/*methods Glucose/chemistry Glutamates/analysis/*chemistry Odorants/analysis Pyrazines/analysis/*chemistry Taste Tea/*chemistry Volatile Organic Compounds/*analysis/chemistry Glucose Manufacturing process Strecker de; |
| Notes: | "MedlineGuo, Xiangyang Song, Chuankui Ho, Chi-Tang Wan, Xiaochun eng England 2018/05/23 Food Chem. 2018 Oct 15; 263:18-28. doi: 10.1016/j.foodchem.2018.04.117. Epub 2018 Apr 27" |
