Nosespace analysis by PTR-ToF-MS for the characterization of food and tasters: the case study of coffee

In the present work Proton Transfer Reaction-Mass Spectrometry was employed in the discrimination of coffee brews by means of nosespace analysis. Three different roasted and ground coffee samples originating from a single pure Arabica blend (medium roast, dark roast and decaffeinated medium roast) were prepared using a stove-top coffee maker. Coffees were submitted to five panelists over three replicates (45 sessions overall). In agreement with the results of brewed coffee headspace analysis, the nosespace data showed that greater differences could be encountered when different roast degrees were compared, rather than decaffeinated and non-decaffeinated. The comparison between headspace and nosespace analysis also showed that different coffees could be discriminated using different subsets of mass peaks, depending upon the mode of analysis. The results also disclosed the existence of reproducible and relevant differences between panelists, also in terms of discrimination ability