Zhou Jingtao, He Chang, Qin Muxue, Luo Qianqian, Jiang Xinfeng, Zhu Junyu, Qiu Li, Yu Zhi, Zhang De, Chen Yuqiong, Ni Dejiang
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
Jiangxi Sericulture and Tea Research Institute, Nanchang, Jiangxi 330202, China.
J Agric Food Chem. 2023 Oct 11;71(40):14706-14719. doi: 10.1021/acs.jafc.3c02813. Epub 2023 Sep 26.
Fermentation is the key technology for black tea aroma formation. The key aroma substances of black tea at different fermentation stages (unfermented (WDY), underfermented (F1H), fully fermented (F4H), and overfermented (F8H)) were characterized by the methodology of Sensomics. Aroma extract dilution analysis was performed on volatile fractions extracted by using solvent-assisted flavor evaporation and solid-phase microextraction, yielding 93 odor-active areas. Internal standard method plus stable isotope dilution analysis was used for quantitative analysis. The omission experiment identified 23 aroma substances. Further reduction and addition experiments revealed phenylacetaldehyde, (,)-2,4-heptadienal, geraniol, linalool, β-damascenone, 2-methylbutyraldehyde, dimethyl sulfide, and isovaleraldehyde with odor activity values (OAV) > 100 as the characteristic aroma components of F4H and also as the main contributors to aroma differences between different fermentation degrees. The green odor of (,)-2,4-heptadienal was highlighted in WDY and F1H relative to that in F4H due to the lower contribution of phenylacetaldehyde and damascenone in the former two samples. Additionally, excessive OAV increase of fatty aldehydes in F8H masked its similar floral and fruity aroma.
发酵是红茶香气形成的关键技术。采用感官组学方法对不同发酵阶段（未发酵（WDY）、发酵不足（F1H）、完全发酵（F4H）和发酵过度（F8H））红茶的关键香气物质进行了表征。对采用溶剂辅助风味蒸发和固相微萃取提取的挥发性成分进行香气提取物稀释分析，得到93个气味活性区域。采用内标法结合稳定同位素稀释分析进行定量分析。遗漏实验鉴定出23种香气物质。进一步的减量和添加实验表明，气味活性值（OAV）>100的苯乙醛、（，）-2,4-庚二烯醛、香叶醇、芳樟醇、β-大马酮、2-甲基丁醛、二甲基硫醚和异戊醛是F4H的特征香气成分，也是不同发酵程度之间香气差异的主要贡献者。由于前两个样品中苯乙醛和大马酮的贡献较低，（，）-2,4-庚二烯醛的青气在WDY和F1H中相对于F4H更为突出。此外，F8H中脂肪醛的OAV过度增加掩盖了其类似的花香和果香。
