title: Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.
abstract: Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract.
authors.affiliation: Department of Nutritional and Food Sciences - Molecular Food Technology, University of Bonn, Bonn, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Damm
authors.affiliation: Institut Prof. Dr. Georg Kurz GmbH, Köln, Germany.
authors.forename: Eileen
authors.initials: E
authors.lastname: Enger
authors.affiliation: Institute of Forensic Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Chrubasik-Hausmann
authors.affiliation: Department of Nutritional and Food Sciences - Molecular Food Technology, University of Bonn, Bonn, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schieber
authors.affiliation: Department of Nutritional and Food Sciences - Molecular Food Technology, University of Bonn, Bonn, Germany.|Institut Prof. Dr. Georg Kurz GmbH, Köln, Germany.
authors.forename: Benno F
authors.initials: BF
authors.lastname: Zimmermann
mesh_terms: D002099:Cacao / Q000737:chemistry* / Q000378:metabolism; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D010936:Plant Extracts / Q000032:analysis* / Q000302:isolation & purification* / Q000378:metabolism; D059808:Polyphenols / Q000737:chemistry* / Q000302:isolation & purification*; D064210:Secondary Metabolism
chemical_list: D010936:Plant Extracts; D059808:Polyphenols
keywords: Chocolate; Cocoa; Flavanols; Liquid chromatography; Pressurized liquid extraction