First Identification of 4-S-Glutathionyl-4-methylpentan-2-one, a Potential Precursor of 4-Mercapto-4-methylpentan-2-one, in Sauvignon Blanc Juice

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• 作者：Bruno Fedrizzi ; Kevin H. Pardon ; Mark A. Sefton ; Gordon M. Elsey ; David W. Jeffery
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2009
• 出版时间：February 11, 2009
• 年：2009
• 卷：57
• 期：3
• 页码：991-995
• 全文大小：231K
• 年卷期：v.57,no.3(February 11, 2009)
• ISSN：1520-5118

文摘

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.