Centre des Sciences du Goût et de l'Alimentation (CSGA), AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, 17, rue Sully, 21065, Dijon, France.
Centre de Recherche Pernod Ricard, 94046, Créteil, France.
Anal Bioanal Chem. 2021 May;413(12):3349-3368. doi: 10.1007/s00216-021-03275-x. Epub 2021 Mar 13.
The headspace volatile organic compound (VOC) fingerprints (volatilome) of French wine brandies were investigated by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Protonated ethanol chemical ionization was used with dedicated experimental conditions that were previously validated for model wines. These included a reference vial containing a hydro-alcoholic solution with the same ethanol content (20% v/v) as the diluted sample spirits, which was used to establish steady-state ionization conditions. A low electric field strength to number density ratio E/N (85 Td) was used in the drift tube in order to limit the fragmentation of the protonated analytes. The obtained headspace fingerprints were used to investigate the origin of French brandies produced within a limited geographic production area. Brandies of two different vintages (one freshly distilled and one aged for 14 years in French oak barrels) were successfully classified according to their growth areas using unsupervised (principal component analysis, PCA) and supervised (partial least squares regression discriminant analysis, PLS-DA) multivariate analyses. The models obtained by PLS-DA allowed the identification of discriminant volatile compounds that were mainly characterised as key aroma compounds of wine brandies. The discrimination was supported by sensory evaluation conducted with free sorting tasks. The results showed that this ethanol ionization method was suitable for direct headspace analysis of brandies. They also demonstrated its ability to distinguish French brandies according to their growth areas, and this effect on brandy VOC composition was confirmed at a perceptive level.
采用质子转移反应飞行时间质谱（PTR-ToF-MS）研究了法国白兰地的顶空挥发性有机化合物（VOC）指纹图谱（挥发谱）。采用质子化乙醇化学电离，同时采用了专门的实验条件，这些条件之前已在模型葡萄酒中得到验证。这些条件包括一个参考小瓶，其中包含与稀释样品烈酒相同乙醇含量（20%v/v）的水醇溶液，用于建立稳定的离子化条件。在漂移管中使用低电场强度与数密度比 E/N（85 Td），以限制质子化分析物的断裂。所得顶空指纹图谱用于研究在有限的地理生产区域内生产的法国白兰地的起源。使用无监督（主成分分析，PCA）和监督（偏最小二乘回归判别分析，PLS-DA）多元分析，根据其生长区域成功地对两种不同年份（一种新鲜蒸馏，一种在法国橡木桶中陈酿 14 年）的白兰地进行了分类。通过 PLS-DA 获得的模型允许鉴定出具有判别性的挥发性化合物，这些化合物主要是葡萄酒白兰地的关键香气化合物。通过自由分类任务进行感官评估支持了这种区分。结果表明，该乙醇电离方法适用于白兰地的直接顶空分析。它们还证明了其根据生长区域区分法国白兰地的能力，并且这种对白兰地 VOC 组成的影响在感知水平上得到了证实。
