eprintid: 17836 rev_number: 6 eprint_status: archive userid: 2 dir: disk0/00/01/78/36 datestamp: 2025-09-08 23:30:11 lastmod: 2025-09-08 23:30:12 status_changed: 2025-09-08 23:30:11 type: article metadata_visibility: show creators_name: Zhao, Yuxuan creators_name: Liang, Jingyimei creators_name: Ma, Wanning creators_name: Farag, Mohamed A. creators_name: Li, Chunlin creators_name: Xiao, Jianbo title: LC-MS and GC–MS analyses reveal that amino acid-induced ammoniation of EGCG in different tea types enhances its structural stability ispublished: pub subjects: uneat_sn divisions: uneatlantico_produccion_cientifica full_text_status: none abstract: Epigallocatechin gallate (EGCG) is the most abundant polyphenol in tea. Owing to the different fermentation degrees, differences in polyphenol composition of water extracts of green tea, white tea, oolong tea, and black tea occur, and affect health value. This study revealed that the content of EGCG decreases with the increase in the degree of fermentation. In tea with a high fermentation degree, EGCG was stably present in the form of ammoniation to yield nitrogen-containing EGCG derivative (N-EGCG). The content of N-EGCG in tea was negatively correlated with the content of EGCG. Furthermore, the content of l-serine and L-threonine in tea was positively and negatively correlated with N-EGCG and EGCG levels, respectively, suggesting that they may participate in the formation of N-EGCG as nitrogen sources. This study proposes a new fermentation-induced polyphenol-amino acid synergistic mechanism, which provides a theoretical basis for the study of the biotransformation reaction mechanism of tea polyphenols. date: 2025-11 publication: Food Chemistry volume: 493 pagerange: 146024 id_number: doi:10.1016/j.foodchem.2025.146024 refereed: TRUE issn: 03088146 official_url: http://doi.org/10.1016/j.foodchem.2025.146024 access: close language: en citation: Artículo Materias > Alimentación Universidad Europea del Atlántico > Investigación > Artículos y libros Cerrado Inglés Epigallocatechin gallate (EGCG) is the most abundant polyphenol in tea. Owing to the different fermentation degrees, differences in polyphenol composition of water extracts of green tea, white tea, oolong tea, and black tea occur, and affect health value. This study revealed that the content of EGCG decreases with the increase in the degree of fermentation. In tea with a high fermentation degree, EGCG was stably present in the form of ammoniation to yield nitrogen-containing EGCG derivative (N-EGCG). The content of N-EGCG in tea was negatively correlated with the content of EGCG. Furthermore, the content of l-serine and L-threonine in tea was positively and negatively correlated with N-EGCG and EGCG levels, respectively, suggesting that they may participate in the formation of N-EGCG as nitrogen sources. This study proposes a new fermentation-induced polyphenol-amino acid synergistic mechanism, which provides a theoretical basis for the study of the biotransformation reaction mechanism of tea polyphenols. metadata Zhao, Yuxuan; Liang, Jingyimei; Ma, Wanning; Farag, Mohamed A.; Li, Chunlin y Xiao, Jianbo mail SIN ESPECIFICAR (2025) LC-MS and GC–MS analyses reveal that amino acid-induced ammoniation of EGCG in different tea types enhances its structural stability. Food Chemistry, 493. p. 146024. ISSN 03088146