State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China; International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education, Anhui Agricultural University, Hefei 230036, China.
Department of Flavor Chemistry, University of Hohenheim, Stuttgart 70599, Germany.
Food Chem. 2025 Jan 15;463(Pt 1):141143. doi: 10.1016/j.foodchem.2024.141143. Epub 2024 Sep 5.
Cooked note is an undesired flavor in green tea, while the key odorants and inhibition mechanisms were unknown. Here, volatiles of four green tea samples and two thermal reaction models of methionine-glucose and methional were assessed using gas chromatography‑sulfur chemiluminescence detector and two dimensional gas chromatography-time-of-flight mass spectrometry. Nonvolatiles of reaction models were determined using ultra performance liquid chromatography-Q-Exactive orbitrap mass spectrometry. Four cooked smelling sulfur-containing odorants including dimethyl trisulfide, dimethyl sulfide, diethyl disulfide, and methanethiol having odor activity values > 1 were characterized in tea samples. Aroma addition tests confirmed dimethyl trisulfide (> 0.4 μg/L) as a reliable predictor of the cooked note. Seven sulfur-containing odorants were detected in reaction models. The addition of (-)-epigallocatechin gallate depleted glucose and interrupted the reaction, thus reduced sulfur-containing odorants' amounts. The study provides a novel insight on targeted strategic guidance for mitigating cooked off-flavor during the thermal processing of green tea production.
炒制味是绿茶中不受欢迎的味道，而关键的气味物质和抑制机制尚不清楚。在这里，使用气相色谱-硫化学发光检测器和二维气相色谱-飞行时间质谱法评估了四种绿茶样品和两种蛋氨酸-葡萄糖和甲硫醛的热反应模型的挥发性。使用超高效液相色谱-Q-Exactive orbitrap 质谱法测定了反应模型的非挥发性物质。在茶样中鉴定出四种具有气味活性值>1 的含硫炒制气味的含硫化合物，包括二甲基三硫化物、二甲基硫、二乙基二硫化物和甲硫醇。香气添加试验证实二甲基三硫化物（>0.4μg/L）是炒制味的可靠预测因子。在反应模型中检测到七种含硫气味物质。（-）-表没食子儿茶素没食子酸酯的添加耗尽了葡萄糖并中断了反应，从而减少了含硫气味物质的含量。该研究为绿茶生产热加工过程中减轻炒制异味提供了新的有针对性的战略指导。
