Key Laboratory of Tea Biology and Resource Utilization of Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Key Laboratory of Tea Biology and Resource Utilization of Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
Food Res Int. 2020 Apr;130:108908. doi: 10.1016/j.foodres.2019.108908. Epub 2019 Dec 18.
Longjing tea is the most famous premium green tea, and is regarded as the national tea in China, with its attractive aroma contributing as a prime factor for its general acceptability; however, its key aroma compounds are essentially unknown. In the present study, volatile compounds from Longjing tea were extracted and examined using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS). Data obtained from the present study revealed that 151 volatile compounds from 16 different chemical classes were identified by GC-MS analysis. Enols (8096 µg/kg), alkanes (6744 µg/kg), aldehydes (6442 µg/kg), and esters (6161 µg/kg) were the four major chemical classes and accounted for 54% of the total content of volatile compounds. Geraniol (6736 µg/kg) was the most abundant volatile compound in Longjing tea, followed by hexanal (1876 µg/kg) and β-ionone (1837 µg/kg). Moreover, 14 volatile compounds were distinguished as the key aroma compounds of Longjing tea based on gas chromatography-olfactometry (GC-O) analysis, odor activity value (OAV) calculations, and a preliminary aroma recombination experiment, including 2-methyl butyraldehyde, dimethyl sulfoxide, heptanal, benzaldehyde, 1-octen-3-ol, (E, E)-2,4-heptadienal, benzeneacetaldehyde, linalool oxide I, (E, E)-3,5-octadien-2-one, linalool, nonanal, methyl salicylate, geraniol, and β-ionone. This is the first comprehensive report describing the aroma characterizations and the key aroma compounds in Longjing tea using SBSE/GC-MS. The findings from this study contribute to the scientific elucidation of the chemical basis for the aromatic qualities of Longjing tea.
龙井绿茶是最著名的高级绿茶，被誉为中国国茶，其诱人的香气是其广受认可的主要因素；然而，其关键香气化合物基本上尚未可知。在本研究中，采用搅拌棒吸附萃取（SBSE）结合气相色谱-质谱联用（GC-MS）技术提取和检测了龙井绿茶的挥发性化合物。GC-MS 分析结果显示，从 16 种不同化学类别的 151 种挥发性化合物中鉴定出 151 种。醇类（8096μg/kg）、烷烃类（6744μg/kg）、醛类（6442μg/kg）和酯类（6161μg/kg）是四大主要化学类别的化合物，占挥发性化合物总量的 54%。香叶醇（6736μg/kg）是龙井绿茶中最丰富的挥发性化合物，其次是己醛（1876μg/kg）和β-紫罗兰酮（1837μg/kg）。此外，根据气相色谱-嗅闻（GC-O）分析、气味活度值（OAV）计算和初步香气重组实验，从 14 种挥发性化合物中区分出 14 种为龙井绿茶的关键香气化合物，包括 2-甲基丁醛、二甲基亚砜、庚醛、苯甲醛、1-辛烯-3-醇、（E，E）-2,4-庚二烯醛、苯乙醛、芳樟醇氧化物 I、（E，E）-3,5-辛二烯-2-酮、芳樟醇、壬醛、水杨酸甲酯、香叶醇和β-紫罗兰酮。这是首次采用 SBSE/GC-MS 全面描述龙井绿茶香气特征和关键香气化合物的报告。本研究结果有助于科学阐明龙井绿茶香气品质的化学基础。
