Non-separative headspace solid phase microextraction-mass spectrometry profile as a marker to monitor coffee roasting degree

This study describes a non-separative Headspace-Solid-Phase-Microextraction-Mass-Spectrometry (HS-SPME-MS) approach, in view of its application to on-line monitoring of a roasting process. The system can quickly provide representative and diagnostic fingerprints of the volatile fraction of samples and, in combination with appropriate chemometric pattern-recognition and regression techniques, can successfully be applied to characterize, discriminate and/or correlate patterns with the roasting process. Eighty coffee samples of different varieties, geographical origins and blends were analyzed. The experimental HS-SPME-MS results show that the TIC fingerprint can be used to discriminate the degree of roasting; diagnostic ion abundance(s) or ratios were closely correlated with the roasting process; both could successfully be used as markers or Analytical Decision Makers, to monitor roasting processes on-line, and to define quality and safety of roasted coffee.