Glycosidically bound volatile profiles of green and roasted coffee beans and aromatic potential of the spent coffee ground

Abstract : Coffee volatile compounds formation has been studied for years and the main flavour precursors have been identified. Coffee glycosidically bound volatiles (GBVs) are still underexplored and, yet, can act as aroma precursors during the post-harvesting processing and roasting. Free volatile compounds and GBVs of green coffee beans (CB), roasted CB and spent coffee ground (SCG) were analysed. Roasting led to the formation of a new GBVs pool from green to roasted CB and SCG. Most of the GBVs of green CB were hydrolysed during roasting. On the other hand, pyrroles, cycloketones, pyridines and pyrans were identified for the first time as bound volatiles and occurred only after the roasting process. This study supports the importance of GBVs on coffee aroma formation during the post-harvest processing. The release of the GBVs of roasted CB during brewing could enhance the varietal aromas of industrial ready-to-drink coffees. Furthermore, the SCG GBVs could be used as a new source of natural flavours for perfume industries.