Gancarz Marek, Dobrzański Bohdan, Malaga-Toboła Urszula, Tabor Sylwester, Combrzyński Maciej, Ćwikła Daniel, Strobel Wacław Roman, Oniszczuk Anna, Karami Hamed, Darvishi Yousef, Żytek Alaksandra, Rusinek Robert
Institute of Agrophysics Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland.
Faculty of Production and Power Engineering, University of Agriculture in Krakow, Balicka 116B, 30-149 Krakow, Poland.
Molecules. 2022 Feb 25;27(5):1559. doi: 10.3390/molecules27051559.
The aim of the study was to analyze the process of roasting coffee beans in a convection-conduction roaster (CC) without a heat exchanger and a convection-conduction-radiation roaster (CCR) with a heat exchanger for determination of the aroma profile. The aroma profile was analyzed using the SPME/GC-MS technique, and an Agrinose electronic nose was used to determine the aroma profile intensity. Arabica coffee beans from five regions of the world, namely, Peru, Costa Rica, Ethiopia, Guatemala, and Brazil, were the research material. The chemometric analyses revealed the dominance of azines, alcohols, aldehydes, hydrazides, and acids in the coffee aroma profile. Their share distinguished the aroma profiles depending on the country of origin of the coffee beans. The high content of pyridine from the azine group was characteristic for the coffee roasting process in the convection-conduction roaster without a heat exchanger, which was shown by the PCA analysis. The increased content of pyridine resulted from the appearance of coal tar, especially in the CC roaster. Pyridine has an unpleasant and bitter plant-like odor, and its excess is detrimental to the human organism. The dominant and elevated content of pyridine is a defect of the coffee roasting process in the CC roaster compared to the process carried out in the CCR machine. The results obtained with the Agrinose showed that the CC roasting method had a significant effect on the sensor responses. The effect of coal tar on the coffee beans resulted in an undesirable aroma profile characterized by increased amounts of aromatic volatile compounds and higher responses of Agrinose sensors.
本研究的目的是分析在无热交换器的对流传导式烘焙机（CC）和有热交换器的对流传导辐射式烘焙机（CCR）中烘焙咖啡豆的过程，以确定香气特征。使用固相微萃取/气相色谱-质谱联用技术分析香气特征，并使用Agrinose电子鼻测定香气特征强度。来自世界五个地区（即秘鲁、哥斯达黎加、埃塞俄比亚、危地马拉和巴西）的阿拉比卡咖啡豆作为研究材料。化学计量分析表明，嗪类、醇类、醛类、酰肼类和酸类在咖啡香气特征中占主导地位。它们的含量根据咖啡豆的原产国区分了香气特征。主成分分析表明，无热交换器的对流传导式烘焙机中咖啡烘焙过程的特征是嗪类中的吡啶含量高。吡啶含量增加是由于煤焦油的出现，尤其是在CC烘焙机中。吡啶有一种难闻的、类似植物的苦味，其过量对人体有害。与CCR机器中的烘焙过程相比，CC烘焙机中咖啡烘焙过程的缺陷是吡啶含量占主导且升高。使用Agrinose获得的结果表明，CC烘焙方法对传感器响应有显著影响。煤焦油对咖啡豆的影响导致了不良的香气特征，其特点是芳香挥发性化合物含量增加，Agrinose传感器的响应更高。
