Fedrizzi Bruno, Pardon Kevin H, Sefton Mark A, Elsey Gordon M, Jeffery David W
Chemical Sciences Department, University of Padova, Padova, Italy.
J Agric Food Chem. 2009 Feb 11;57(3):991-5. doi: 10.1021/jf802799w.
The identification of 4-S-glutathionyl-4-methylpentan-2-one (glut-4-MMP) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) experiments in a Sauvignon Blanc juice extract is described. Synthesis of an authentic reference compound enabled confirmation of the presence of glut-4-MMP in a Sauvignon Blanc juice for the first time. The juice extract was obtained by batch-wise percolation of 6 L of juice through a sintered glass funnel packed with C18 sorbent, followed by further purification using low-pressure chromatography on C18. Analysis of the juice extract revealed a chromatographic peak with the same retention time and mass spectrum as the synthetic reference compound, and spiking experiments verified the findings. The presence of glut-4-MMP in grape juice may be related to the biosynthesis of the relevant S-cysteinyl conjugate and, subsequently, to the formation of aroma-active 4-mercapto-4-methylpentan-2-one (4-MMP). This compound has a very low reported sensory threshold (3 ng/L) in wine and is partially responsible for the aromas that are important to the quality and style of some wine varieties.
本文描述了通过高效液相色谱-串联质谱（HPLC-MS/MS）实验在长相思葡萄汁提取物中鉴定4-S-谷胱甘肽基-4-甲基戊-2-酮（glut-4-MMP）的过程。合成了一种真实的参考化合物，首次证实了长相思葡萄汁中存在glut-4-MMP。通过将6升葡萄汁分批通过填充有C18吸附剂的烧结玻璃漏斗进行渗滤，然后在C18上进行低压色谱进一步纯化，从而获得葡萄汁提取物。对葡萄汁提取物的分析显示，有一个色谱峰，其保留时间和质谱与合成参考化合物相同，加标实验验证了这一结果。葡萄汁中glut-4-MMP的存在可能与相关S-半胱氨酰共轭物的生物合成有关，进而与香气活性物质4-巯基-4-甲基戊-2-酮（4-MMP）的形成有关。该化合物在葡萄酒中的感官阈值极低（3 ng/L），对某些葡萄酒品种的品质和风格所具有的重要香气有部分贡献。
