A Further Tool To Monitor Coffee Roasting Process: Aroma Composition And Chemical Indices

Coffee quality is strictly related to its flavor and aroma developed during the roasting process, that, in their turn, depend on variety and origin, harvest and post-harvest practices, as well as time, temperature and degree of roasting. This study investigates the possibility to combine chemical (aroma components) and physical (color) parameters through chemometric approaches to monitor roasting process, degree of roasting and aroma formation by analyzing a suitable number of coffee samples from different varieties and blends. In particular, a correlation between the aroma composition of roasted coffee obtained by HS-SPME-GC-MS and degree of roasting, defined by the color, has been searched. The results showed that aroma components are linearly correlated to coffee color with a correlation factor of 0.9387. The study continued looking for chemical indices: eleven indices were found to be linearly correlated to the color resulting from the roasting process, the most effective of them being 5-methyl furfural/2-acetyl furan ratio (index).