Agricultural Institute of Slovenia, Department of Fruit Growing, Viticulture and Oenology and Central Laboratory, Hacquetova ulica 17, 1000, Ljubljana, Slovenia.
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000, Ljubljana, Slovenia.
Sci Rep. 2017 Oct 13;7(1):13122. doi: 10.1038/s41598-017-13273-8.
Varietal thiol precursors in grapes are subject to metabolic changes during post-harvest treatments. Metabolic activity should therefore be limited after sampling to understand their biosynthesis in the berry and genetic regulation. In this study, berries were frozen in liquid nitrogen immediately after harvesting, transported in dry ice, stored briefly at -80 °C, cryo-milled and extracted without being thawed in cold methanol in a ratio of 1:4 (w/v). A UHPLC-MS/MS method for quantitative determination of the thiol precursors 3-S-glutathionylhexan-1-ol (G3MH), 3-S-cysteinylhexan-1-ol (Cys3MH), 4-S-glutathionyl-4-methylpentan-2-one (G4MMP) and 4-S-cysteinyl-4-methylpentan-2-one (Cys4MMP), glutathione, oxidized glutathione and L-methionine in grapes was developed. Reference material was provided through synthesis of precursors and their deuterium labelled analogues. The average thiol precursor content in grapes in 2013-15 was in the range 8-16 μg kg for G3MH, 1-6 μg kg for Cys3MH, 1-4 μg kg for Cys4MMP and 0.3 μg kg for G4MMP. In 2013 and 2014, the highest precursor content in mature Sauvignon Blanc grapes from vineyards located in Italy regarded G3MH, followed by Cys3MH, Cys4MMP and G4MMP. In 2015, G3MH was again the most abundant precursor, but followed by Cys4MMP, Cys3MH and G4MMP.
葡萄中的品种硫醇前体在收获后处理过程中会发生代谢变化。因此，为了了解浆果中它们的生物合成和遗传调控，在采样后应限制代谢活性。在这项研究中，葡萄在收获后立即用液氮冷冻，用干冰运输，短暂储存在-80°C 下，然后在冷甲醇中以 1:4（w/v）的比例进行 cryo-milling 和提取，无需解冻。建立了一种用于定量测定硫醇前体 3-S-谷胱甘肽己烷-1-醇（G3MH）、3-S-半胱氨酸己烷-1-醇（Cys3MH）、4-S-谷胱甘肽-4-甲基戊-2-酮（G4MMP）和 4-S-半胱氨酸-4-甲基戊-2-酮（Cys4MMP）、谷胱甘肽、氧化谷胱甘肽和 L-蛋氨酸在葡萄中的 UHPLC-MS/MS 方法。通过前体及其氘标记类似物的合成提供了参考物质。2013-15 年葡萄中硫醇前体的平均含量范围为 G3MH 8-16μgkg，Cys3MH 1-6μgkg，Cys4MMP 1-4μgkg，G4MMP 0.3μgkg。在 2013 年和 2014 年，意大利葡萄园成熟长相思葡萄中含量最高的前体为 G3MH，其次为 Cys3MH、Cys4MMP 和 G4MMP。2015 年，G3MH 再次成为最丰富的前体，但其次是 Cys4MMP、Cys3MH 和 G4MMP。
