Spatial distributions of furan and 5-hydroxymethylfurfural in unroasted and roasted Coffea arabica beans

Abstract

For the first time, the spatial distributions of the highly volatile compounds furan and 5-hydroxymethylfurfural (HMF) have been determined in cross sections of green and roasted Coffea arabica beans. The image maps were revealed by laser ablation DART imaging mass spectrometry (LADI-MS). The presence of these compounds was independently confirmed by GC-MS as well as argon DART-MS. Quantification of furan by GC-MS was completed with the final concentrations in roasted and unroasted beans determined to be 96.5 and 4.1 ng/g, respectively. Furan was observed to be distributed throughout the tissue of both green and roasted beans, while HMF was localized to the silver skin in green beans. Following roasting, the appearance of HMF was more diffuse. The implications of the broad distribution of furan on the one hand, and localization of HMF on the other, are discussed.

Keywords: 5-Hydroxymethylfurfural; Coffea arabica beans; Furan; Imaging mass spectrometry; Laser ablation direct analysis in real time imaging-mass spectrometry (LADI-MS); Small-molecule spatial distributions.