High‐performance liquid chromatography with fluorescence detection fingerprints as chemical descriptors to authenticate the origin, variety and roasting degree of coffee by multivariate chemometric methods

Abstract

BACKGROUND: Coffee is one of the most popular beverages around the world, consumed as an infusion of ground roasting coffee beans with a characteristic taste and flavor. Two main varieties, Arabica and Robusta, are worldwide produced. Besides, the interest of consumers in quality attributes related to coffee production region and varieties is increasing, being necessary encouraging the development of simple methodologies to authenticate and to guarantee the coffee origin, variety, as well as the roasting degree to prevent fraudulent practices. RESULTS: C18 high-performance liquid chromatography with fluorescence detection (HPLC-FLD) fingerprints obtained after brewing the coffees without any sample treatment other than filtration (considerably reducing sample manipulation) were employed as sample chemical descriptors for coffee characterization and classification by principal component analysis (PCA) and partial least squares regression-discriminant analysis (PLS-DA). PLS-DA showed good classification capabilities regarding coffee origin, variety and roasting degree when employing HPLC-FLD fingerprints although overlapping for some sample groups occurred. However, the discrimination power increased when selecting HPLC-FLD fingerprinting segments richer in discriminant features, which were deduced from PLS-DA loading plots. In this case, excellent separation was observed and 100% classification rates for both PLS-DA calibrations and predictions were obtained (all samples were correctly classified within their corresponding groups). CONCLUSION: HPLC-FLD fingerprinting segments resulted to be suitable chemical descriptors to discriminate the origin (country of production), variety (Arabica and Robusta) and roasting degree of coffee. Therefore, HPLC-FLD fingerprinting can be proposed as a feasible, simple and cheap methodology to address coffee authentication, especially for developing coffee production countries.