Department of Food and Drug, University of Parma, 43124 Parma, Italy.
Institute of Cancer and Genomic Sciences, Centre for Computational Biology, University of Birmingham, B15 2TT, UK.
Molecules. 2020 Mar 5;25(5):1166. doi: 10.3390/molecules25051166.
Coffee capsules market is on the rise as it allows access to a wide selection of coffee, differing in taste and brand. However, few data about the chemical characterization of the capsule-brewed coffee aroma are available. In this work, an untargeted approach using headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) and combined to chemometrics was performed to study and compare aroma profile from 65 capsule-brewed espresso coffees (ECs) commercialized by five of the most representative brands in Italy. Volatile profiles obtained from ECs were subjected to multivariate statistical analysis, which generally did not show a significant variability among coffees belonging to the same brand, except for those modified after the addition of specific flavor additives or aromatic substances (such as caramel, chocolate, etc.). Similarities may be related to the starting coffee brew or the processing method, which is likely the same for each individual brand. Additionally, partial least squares discriminant analysis (PLS-DA) showed that capsules from a specific brand contain the highest concentration of pyrazines, thus characterized by an intense and characteristic aroma, and a stronger note than those from the other brands. This study supports that the chemical analysis in conjunction with chemometric tools is a useful approach for assessing flavor quality, even if the need remains to identify volatile markers of high-quality beverages.
咖啡胶囊市场日益兴起，因为它可以让人们接触到各种不同口味和品牌的咖啡。然而，关于胶囊冲泡咖啡香气的化学特征，目前的数据还很少。在这项工作中，采用顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）和化学计量学的非靶向方法，研究并比较了来自意大利五个最具代表性品牌的 65 种胶囊冲泡浓咖啡（EC）的香气特征。从 EC 中获得的挥发性图谱经过多元统计分析，除了那些经过特定风味添加剂或芳香物质（如焦糖、巧克力等）添加后进行改性的咖啡之外，通常不会显示出属于同一品牌的咖啡之间有显著的差异。相似性可能与起始咖啡酿造或加工方法有关，因为每个品牌的加工方法可能相同。此外，偏最小二乘判别分析（PLS-DA）表明，特定品牌的胶囊含有最高浓度的吡嗪，因此具有浓郁且独特的香气，比其他品牌的香气更强烈。这项研究表明，化学分析结合化学计量学工具是评估风味质量的一种有用方法，即使仍需要确定高品质饮料的挥发性标志物。
