Assessment of green coffee bean metabolites dependent on coffee quality using a 1H NMR-based metabolomics approach

•Comprehensive metabolites related to high-graded green coffee bean, specialty bean, were identified.•The relationship between variation in green coffee bean metabolites and its quality were explored in the Arabica coffee bean of single species.•Metabolomic approach provides a multiple markers to assess the quality of green coffee bean.

There is increasing interest in the coffee grade or quality with the rise of coffee consumption, but a classical, chemical analysis-based understanding of the coffee bean grade is still limited. We therefore report the identification of green coffee bean metabolites related to coffee bean quality using a 1H NMR-based metabolomic analysis of well-established specialty-grade green coffee beans, in particular, of a single species (Coffea arabica). The higher levels of sucrose and the lower levels of γ-aminobutyric acid (GABA), quinic acid, choline, acetic acid and fatty acids observed in specialty or high-grade green coffee beans, compared to commercial-grade beans, were suggestive to be multiple markers for characterizing specialty green coffee bean. In particular, variations in sucrose and GABA levels between specialty and commercial coffees could be a consequence of different environmental conditions, for example, biotic or abiotc stresses, at growing regions. These results highlight an alternative method of metabolomic approach for grading green coffee bean.