State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
Guizhou Tea Institute, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou 550006, China.
Food Chem. 2022 Nov 30;395:133549. doi: 10.1016/j.foodchem.2022.133549. Epub 2022 Jun 23.
Withering is a key process that affects the aroma of Keemun black tea (KBT). In this study, the aroma composition of KBT through natural withering, sun withering, and warm-air withering was analysed using gas chromatography-mass spectrometry. The results revealed significant differences in the three samples. Gas chromatography-olfactometry and aroma extract dilution analysis were performed with screening through a relative odour activity value (rOAV) > 1. In total, 11 aroma-active compounds (geraniol, (Z)-4-heptenal, 1-octen-3-ol, (E)-β-ionone, 3-methylbutanal, linalool, β-damascenone, (E, E)-2,4-decadienal, methional, (E, E)-2,4-nonadienal, and (E)-2-nonenal) were found to be responsible for the differences in aroma caused by different withering methods. Linalool (rOAV, 161) and geraniol (rOAV, 785) were responsible for the higher flowery and fruity aromas when sun withering was applied, whereas methional (rOAV, 124) contributed to the intense roasty aroma when warm-air withering was employed. Moreover, our results were verified by quantitative descriptive analysis and addition experiments.
萎凋是影响祁门红茶（KBT）香气的关键过程。本研究采用气相色谱-质谱联用技术分析了自然萎凋、阳光萎凋和暖风萎凋 KBT 的香气成分。结果表明，这三种样品存在显著差异。采用气相色谱-嗅觉测量法和香气提取物稀释分析，通过相对气味活度值（rOAV）筛选>1 的化合物。共鉴定出 11 种香气活性化合物（香叶醇、（Z）-4-庚烯醛、1-辛烯-3-醇、（E）-β-紫罗兰酮、3-甲基丁醛、芳樟醇、β-大马酮、（E，E）-2,4-癸二烯醛、甲硫醛、（E，E）-2,4-壬二烯醛和（E）-2-壬烯醛），这些化合物是导致不同萎凋方法产生不同香气的原因。当采用阳光萎凋时，香叶醇（rOAV，161）和香叶醇（rOAV，785）导致了更高的花香和果香，而当采用暖风萎凋时，甲硫醛（rOAV，124）导致了强烈的烤焦香气。此外，我们的结果通过定量描述性分析和添加实验得到了验证。
