title: Two-dimensional 1H-13C nuclear magnetic resonance (NMR)-based comprehensive analysis of roasted coffee bean extract.
abstract: Coffee was characterized by proton and carbon nuclear magnetic resonance (NMR) spectroscopy. To identify the coffee components, a detailed and approximately 90% signal assignment was carried out using various two-dimensional NMR spectra and a spiking method, in which authentic compounds were added to the roasted coffee bean extract (RCBE) sample. A total of 24 coffee components, including 5 polysaccharide units, 3 stereoisomers of chlorogenic acids, and 2 stereoisomers of quinic acids, were identified with the NMR spectra of RCBE. On the basis of the signal assignment, state analyses were further launched for the metal ion-citrate complexes and caffeine-chlorogenate complexes. On the basis of the signal integration, the coffee components were successfully quantified. This NMR methodology yielded detailed information on RCBE using only a single observation and provides a systemic approach for the analysis of other complex mixtures.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Feifei
authors.initials: F
authors.lastname: Wei
authors.forename: Kazuo
authors.initials: K
authors.lastname: Furihata
authors.forename: Fangyu
authors.initials: F
authors.lastname: Hu
authors.forename: Takuya
authors.initials: T
authors.lastname: Miyakawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanokura
mesh_terms: D002726:Chlorogenic Acid / Q000032:analysis; D040503:Coffea / Q000737:chemistry*; D003069:Coffee / Q000737:chemistry; D006358:Hot Temperature; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010936:Plant Extracts / Q000737:chemistry; D011134:Polysaccharides / Q000032:analysis; D011801:Quinic Acid / Q000032:analysis; D012639:Seeds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003069:Coffee; D010936:Plant Extracts; D011134:Polysaccharides; D011801:Quinic Acid; D002726:Chlorogenic Acid