Coffee Metabolomics – a real kick!

Recently, the importance of post-harvest treatments on coffee bean quality has received growing attention, and several studies describe the impact of wet and dry processing on the physiology and quality of coffee. Nevertheless, the metabolic alterations occurring upon drying are not well understood. In this presentation we introduce metabolomics as a promising approach to study comprehensively the metabolite composition of the coffee bean and how this changes during processing. Using both GC and LC coupled to high resolution mass spectrometry, we were able to detect and compare thousands of mass signals representing hundreds of compounds simultaneously. We have studied the alterations in the metabolite profiles upon open air-drying of fresh ripe fruit of Coffea arabica (50% moisture) towards fullydried green coffee beans (11% moisture) and also have followed metabolic changes during the roasting of a large series of coffee (arabica and robusta) genotypes. Various patterns of alterations in relative metabolite abundance upon drying could be discriminated, suggesting differential and specific effects on metabolites and biosynthetic pathways. The example provided clearly indicates that metabolomics can provide novel insights into coffee composition and will greatly enhance our possibilities to find novel markers for quality traits or genotypes, to monitor and control changes occurring upon pre- and postharvest treatments, and to unravel coffee biology.