IASMA Research and Innovation Centre, Fondazione Edmund Mach, Food Quality and Nutrition Department, San Michele all'Adige, Trento, Italy.
Anal Chim Acta. 2012 Jun 30;732:194-202. doi: 10.1016/j.aca.2011.11.051. Epub 2011 Dec 13.
This paper presents methods for the definition of important analytical tools, such as the development of sensitive and rapid methods for analysing reduced and oxidised glutathione (GSH and GSSG), hydroxycinnamic acids (HCA), bound thiols (GSH-3MH and Cys-3MH) and free thiols (3MH and 3MHA), and their first application to evaluate the effect of reductive winemaking on the composition of Lugana juices and wines. Lugana is a traditional white wine from the Lake Garda region (Italy), produced using a local grape variety, Trebbiano di Lugana. An innovative winemaking procedure based on preliminary cooling of grape berries followed by crushing in an inert environment was implemented and explored on a winery scale. The effects of these procedures on hydroxycinnamic acids, GSH, GSSG, free and bound thiols and flavanols content were investigated. The juices and wines produced using different protocols were examined. Moreover, wines aged in tanks for 1, 2 and 3 months were analysed. The high level of GSH found in Lugana grapes, which can act as a natural antioxidant and be preserved in must and young wines, thus reducing the need of exogenous antioxidants, was particularly interesting. Moreover, it was clear that polyphenol concentrations (hydroxycinnamic acids and catechins) were strongly influenced by winemaking and pressing conditions, which required fine tuning of pressing. Above-threshold levels of 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) were found in the wines and changed according to the winemaking procedure applied. Interestingly, the evolution during the first three months also varied depending on the procedure adopted. Organic synthesis of cysteine and glutathione conjugates was carried out and juices and wines were subjected to LC-MS/MS analysis. These two molecules appeared to be strongly affected by the winemaking procedure, but did not show any significant change during the first 3 months of post-bottling ageing. This supports the theory, already proposed in the literature, that there are other synthetic pathways for free thiol formation.
本文提出了定义重要分析工具的方法，例如开发用于分析还原型和氧化型谷胱甘肽（GSH 和 GSSG）、羟基肉桂酸（HCA）、结合硫醇（GSH-3MH 和 Cys-3MH）和游离硫醇（3MH 和 3MHA）的灵敏快速方法，并首次将其应用于评估还原酿造对卢加纳果汁和葡萄酒成分的影响。卢加纳是意大利加尔达湖地区的一种传统白葡萄酒，使用当地的特雷比奥罗葡萄品种酿造。在酿酒厂规模上实施并探索了一种基于预先冷却葡萄浆果然后在惰性环境中破碎的创新酿酒工艺。研究了这些工艺对羟基肉桂酸、GSH、GSSG、游离和结合硫醇以及黄烷醇含量的影响。研究了使用不同方案生产的果汁和葡萄酒。此外，还分析了在罐中陈酿 1、2 和 3 个月的葡萄酒。卢加纳葡萄中发现的高水平 GSH 特别有趣，它可以作为一种天然抗氧化剂，保存在葡萄汁和年轻的葡萄酒中，从而减少对外源性抗氧化剂的需求。此外，多酚浓度（羟基肉桂酸和儿茶素）强烈受到酿酒和压榨条件的影响，这需要对压榨进行微调，这一点很明显。葡萄酒中发现了超过阈值水平的 3-巯基己醇（3MH）和 3-巯基己基乙酸酯（3MHA），并且根据应用的酿酒工艺而变化。有趣的是，在头三个月的演变也根据采用的工艺而有所不同。进行了半胱氨酸和谷胱甘肽缀合物的有机合成，并对果汁和葡萄酒进行了 LC-MS/MS 分析。这两种分子似乎受到酿酒工艺的强烈影响，但在装瓶后老化的前 3 个月内没有显示出任何显著变化。这支持了文献中已经提出的理论，即存在其他形成游离硫醇的合成途径。
