Insight into the Time-Resolved Extraction of Aroma Compounds during Espresso Coffee Preparation: Online Monitoring by PTR-ToF-MS
Insight into the Time-Resolved Extraction of Aroma Compounds during Espresso Coffee Preparation: Online Monitoring by PTR-ToF-MS
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DOI：
10.1021/ac502992k
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发表时间：
2014-12-02
影响因子：
7.4
通讯作者：
Yeretzian, Chahan
中科院分区：
文献类型：
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作者：
Sanchez-Lopez, Jose A.;Zimmermann, Ralf;Yeretzian, Chahan
使用质子转移反应飞行时间质谱 (PTR-ToF-MS)，我们研究了浓缩咖啡制备过程中 95 个离子痕量的实时提取动态（时间分辨率 = 1 秒）。初步鉴定出其中 52 个离子。这是通过在浓缩咖啡机（单份胶囊）萃取软管出口处对咖啡流附近的挥发性有机化合物 (VOC) 进行在线采样来实现的。根据相应咖啡胶囊（Ristretto、Espresso 和 Lungo）的推荐杯子尺寸，对六种不同单杯咖啡类型进行十次重复提取，最终重量在 20120 克之间，并进行分析。结果揭示了化合物之间的提取动力学存在显着差异，这导致提取物流中挥发性曲线的快速演变，从而导致杯中最终香气平衡的演变。除了探索 VOC 的时间分辨萃取动力学之外，动态数据还可以区分咖啡类型（胶囊）。层次聚类分析 (HCA) 和主成分分析 (PCA) 均显示咖啡类型之间完全分离。开发的方法提供了一种快速而简单的方法来研究挥发性有机化合物的提取动力学并区分不同的咖啡类型。
Using proton-transfer-reaction time-of-flight mass-spectrometry (PTR-ToF-MS), we investigated the extraction dynamic of 95 ion traces in real time (time resolution = 1 s) during espresso coffee preparation. Fifty-two of these ions were tentatively identified. This was achieved by online sampling of the volatile organic compounds (VOCs) in close vicinity to the coffee flow, at the exit of the extraction hose of the espresso machine (single serve capsules). Ten replicates of six different single serve coffee types were extracted to a final weight between 20120 g, according to the recommended cup size of the respective coffee capsule (Ristretto, Espresso, and Lungo), and analyzed. The results revealed considerable differences in the extraction kinetics between compounds, which led to a fast evolution of the volatile profiles in the extract flow and consequently to an evolution of the final aroma balance in the cup. Besides exploring the time-resolved extraction dynamics of VOCs, the dynamic data also allowed the coffees types (capsules) to be distinguished from one another. Both hierarchical cluster analysis (HCA) and principal component analysis (PCA) showed full separation between the coffees types. The methodology developed provides a fast and simple means of studying the extraction dynamics of VOCs and differentiating between different coffee types.