Aroma compositions of large-leaf yellow tea and potential effect of theanine on volatile formation in tea. (15th May 2019)

• Record Type: Journal Article
• Authors: Guo, Xiangyang; Ho, Chi-Tang; Schwab, Wilfried; Song, Chuankui; Wan, Xiaochun
• Is Part Of: Food chemistry. Volume 280(2019)
• Page Start: 73
• Page End: 82
• Publication Date: 2019-05-15
• Subjects: Large-leaf yellow tea -- Volatile compounds -- Tea aroma formation -- Theanine -- Model thermal reaction -- Strecker degradation; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2018.12.066
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Employing three extraction methods to reveal large-leaf yellow tea aroma composition. Heterocyclics and aromatics were the main volatiles of large-leaf yellow tea. N -Ethylacetamide was identified and preliminarily proved to be derived from theanine. l -Theanine when heated alone gave products present in tea aroma. The formation mechanisms of N -ethylformamide and N -ethylacetamide were proposed. Abstract: Large-leaf yellow tea (LYT) imparting unique toasty flavor is a traditional beverage in China. The volatile composition of LYT after full fire processing (FF-YT) was determined by different extraction methods. Steam distillation (SD), solid-phase microextraction (SPME) and headspace (HS) were applied for analysis of tea body notes, tea infusion and dry tea aroma, respectively. A total of 143 volatile compounds was identified by the three methods, of which SD-FF-YT, SPME-FF-YT, and HS-FF-YT extracts contained 100, 72, and 56 volatiles, respectively. Heterocyclics and aromatic compounds were the main volatile composition of LYT and might be contributors to its crispy-rice-like odor.l -Theanine was demonstrated to contribute to the formation of tea volatiles. N -Ethylacetamide, formed in thel -theanine only model thermal reaction, was probably involved in the LYT volatile formation. The current results provide new insight intol -theanine on aroma formation, although the detailed formation mechanism remains largely unknown.