基于全二维气相色谱-质谱联用技术的龙井茶特征香气成分解析

Analysis of characteristic aroma compounds in Longjing tea based on two-dimensional gas chromatography-mass spectrometry

本文采用一维和全二维气相色谱-质谱联用仪,鉴定了2种龙井茶(狮峰、越州)中48个和37个特征香气成分,其中(Z)-4-庚烯醛(0.16〜0.21μg/L)、(E,Z)-2,6-壬二烯醛(0.18〜0.26μg/L)、2-异丁基-3-甲氧基吡嗪(0.02〜0.03μg/L)、2-乙酰基-1-吡咯啉(0.49〜0.61μg/L)、糠硫醇(0.06〜0.09μg/L)等9个微量成分仅在全二维仪器上检出。结合香气活性值、S型曲线法和香气重组实验,发现2-异丁基-3-甲氧基吡嗪、2-乙酰基-1-吡咯啉、3-甲基-2,4-壬二酮、糠基硫醇等对龙井茶重组液的阈值和香气强度值都具有显著的影响。上述结果表明,对关键微量成分的准确鉴定是阐明龙井茶特征香气轮廓的关键。

48 and 37 characteristic aroma compounds in 2 kinds of Longjing tea(Shifeng and Yuezhou)were identified by GC-MS and two-dimensional gas chromatography-mass spectrometry.(Z)-4-Heptenal(0.16〜0.21μg/L),(E,Z)-2,6-nonadienal(0.18〜0.26μg/L),2-isobutyl-3-methoxypyrazine(0.02〜0.03μg/L),2-acetyl-1-pyrroline(0.49〜0.61μg/L),furfuryl mercaptan(0.06〜0.09μg/L)and other trace compounds were only detected by the two-dimensional instrument.Combined with odor activity value,S-curve method and aroma recombination experiment,it was found that 2-isobutyl-3-methoxypyrazine,2-acetyl-1-pyrroline,3-methyl-2,4-nonodione,furfuryl mercaptan had significant effects on the threshold value and aroma intensity value of Longjing tea recombinant liquid.The results above indicated that accurate identification of key trace compounds was crucial for unravelling the distinctive aroma profile of Longjing tea.