title: Study of composition of espresso coffee prepared from various roast degrees of Coffea arabica L. coffee beans.
abstract: Espresso coffee samples prepared at various roasting degrees defined according to its basic conventional classification (light, medium, medium-dark and dark roasted) were analyzed by ultra-performance liquid chromatography/tandem mass spectrometry. Obtained raw data were processed using multivariate statistical analysis (Principal Component Analysis, PCA) to evaluate chemical differences between each roasting degrees (untargeted part of study). All four roasting degrees were resolved in appropriate Score plot. Orthogonal Projections to Latent Structures provided signals of significant markers describing the differences among particular roasting degrees. Detailed interpretation of those signals by targeted LC/MS(2) analysis revealed four groups of compounds. The first two groups involve chlorogenic acids and related lactones. The signals of other two sets of markers were ascribed to some specific atractylosides and particular melanoidins. Ratios of contents of selected representatives of each group to the sum of all identified markers were proposed as definite parameters for determination of roasting degree of Brazilian coffee Arabica.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17.listopadu 12, 779 00 Olomouc, Czech Republic.
authors.forename: Lukáš
authors.initials: L
authors.lastname: Kučera
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17.listopadu 12, 779 00 Olomouc, Czech Republic.
authors.forename: Roman
authors.initials: R
authors.lastname: Papoušek
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17.listopadu 12, 779 00 Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Kurka
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17.listopadu 12, 779 00 Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Barták
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17.listopadu 12, 779 00 Olomouc, Czech Republic. Electronic address: petr.bednar@upol.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Bednář
mesh_terms: D002845:Chromatography / Q000379:methods*; D040503:Coffea / Q000737:chemistry*; D003069:Coffee / Q000737:chemistry*; D006358:Hot Temperature; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D003069:Coffee
keywords: Atractyloside; Chlorogenic acid; Chromatography; Coffee; Lactone; Maillard reaction; Mass spectrometry; Roasting