海南兴隆地区烘焙咖啡豆的挥发性成分研究

以海南兴隆地区的咖啡豆为试材,利用顶空固相微萃取-气相色谱-质谱法(HS-SPME/GC-MS)结合电子鼻对不同烘焙度(浅度、中度、深度)下的咖啡挥发性化合物进行检测。结果表明:烘焙咖啡中共检测出123种化合物,浅度豆检测出90种化合物,主要为酸类和吡嗪类,中度豆检测出103种化合物,主要为酮类、呋喃类、吡嗪类和吡咯类,深度豆检测出118种化合物,主要为呋喃类、吡啶类和酚类;电子鼻传感器可有效分析咖啡挥发性成分变化(除传感器LY2/g CT外),主成分分析(PCA)可有效区分不同烘焙度的咖啡香气。随着烘焙程度加深,咖啡中吡咯类、吡啶类、含硫化合物等挥发性化合物种类和相对含量逐渐增加,吡嗪类和酸类逐渐减少,呋喃类和酮类先增加后减少,进而改变咖啡的特征性香气。HS-SPME/GC-MS与电子鼻技术结合可根据挥发性物质的差异为判断指标,以较好的区分海南兴隆地区不同烘焙度咖啡,为海南兴隆咖啡的烘焙加工提供理论借鉴。

Volatile Components of Roasted Coffee Beans Based on HS-SPME/GC-MS and Electronic Nose inXinglong Region, Hainan Province

The aim of the study is to investigate the relationships between coffee volatile compounds and roasting degree, the differences of coffee volatiles compositions were distinguished based on different roasting degrees. The volatile compounds of coffee were detected by the head space solid phase microextraction-gas chromatographic-mass spectrometric(HS-SPME/GC-MS)and the electronic nose with different roasting degree(light, medium, dark) when the Xinglong coffee beans were used as the experimental materials. The total volatile compounds were detected as 123 kinds, and 90 kinds of these compounds were showed in light roasting(mainly acids and pyrazines). 103 kinds of compounds were detected in medium roasting(mainly ketones, furans, pyrazines and pyrroles), 118 kinds of compounds were detected in dark roasting(mainly furans, pyridines and phenols). Part of the sensors of electronic nose could effectively explore the variation of characteristic flavor of coffee except the sensor LY2/gCT. The principal component analysis(PCA)could effectively discriminate the coffee aroma with different roasting degrees. The kinds and relative content of volatile compounds increased gradually including pyrroles, pyridines and sulfurs. As pyrazines and acids kept decreasing while furans and ketones decreased after the first increased with the roasting degree increasing. Thereby the roasting degree changed the characteristic aroma of coffee. The HS-SPME/GC-MS combined electronic nose could discriminate roasting degrees of coffee samples according to the differences among the volatile compounds of roasted coffee. The research results could provide guidance for the processing of coffee in Xinglong, Hainan.