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Comparative evaluation of the volatile profiles and taste properties of roasted coffee beans as affected by drying method and detected by electronic nose, electronic tongue, and HS-SPME-GC-MS

Dong, Wenjiang, Hu, Rongsuo, Long, Yuzhou, Li, Hehe, Zhang, Yanjun, Zhu, Kexue, Chu, Zhong
Food chemistry 2019 v.272 pp. 723-731
ambient temperature, coffee beans, electronic nose, electronic tongue, esters, freeze drying, gas chromatography-mass spectrometry, headspace analysis, heat pumps, ketones, pH, phenols, principal component analysis, radar, solar drying, solid phase microextraction, taste, titratable acidity, total soluble solids, volatile compounds
In this study, room-temperature drying, solar drying, heat pump drying (HPD), hot-air drying, and freeze drying were applied to investigate the volatile profiles and taste properties of roasted coffee beans by using electronic nose, electronic tongue, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results indicated that the drying process markedly affected pH, total titratable acidity, total solids, and total soluble solids. Significant differences existed among all samples based on drying method; and the HPD method was superior for preserving ketones, phenols, and esters. Principal component analysis (PCA) combined with E-nose and E-tongue radar charts as well as the fingerprint of HS-SPME-GC-MS could clearly discriminate samples from different drying methods, with results obtained from hierarchical cluster analysis (the Euclidean distance is 0.75) being in agreement with those of PCA. These findings may provide a theoretical basis for the dehydration of coffee beans and other similar thermo-sensitive agricultural products.