One of the longest established PTR-MS applications is once again producing fascinating results: Alexia Gloess and her team have just published a PTR-TOF study on coffee roasting that is currently the most downloaded article in IJMS.
It is not surprising that aroma analysis is among the prime applications of PTR-MS. The high sensitivity and real-time capability make PTR-MS an ideal tool for direct VOC quantification. Especially coffee with its rich flavour spectrum has always been in the focus of researchers. It is likely due to this complexity, that this subject is far from exhausted and consistently releases new results.
A team from the Zurich University of Applied Sciences has recently published a study where they have studied coffee samples from different origins – roasted to different degrees and along varying time/temperature roasting profiles. Roasting is the crucial step towards a good cup of coffee, in which the flavour compounds are formed in chemical reactions (Millard reaction), degradation and thermal decomposition processes. The team around Alexia Gloess and Chahan Yeretzian has used proton-transfer-reaction time-of-flight mass-spectrometry, an IONICON PTR-TOF 8000 instrument, to monitor the formation of volatile organic compounds (VOCs) during roasting. The capability to measure on-line gives valuable insights into the dynamic of the VOC production. They have seen that the release dynamics showed a strong modulation with the roasting profile. More surprisingly, this effect varies for coffee samples from different origins. This demonstrates that coffee is a unique product, its flavour equally depending on its origin and the roasting process.
Their findings have now been published in the International Journal of Mass Spectrometry (IJMS) in the article “Evidence of different flavour formation dynamics by roasting coffee from different origins: On-line analysis with PTR-ToF-MS” (download PDF). This article is currently on first [date 17.2.20] place on Most Downloaded IJMS Articles.