title: Identification of proline-based diketopiperazines in roasted coffee.
abstract: Five proline-based diketopiperazines were identified in water extracts of roasted coffee proteins and roasted coffee itself. These are cyclo(pro-ile), cyclo(pro-leu), cyclo(pro-phe), cyclo(pro-pro), and cyclo(pro-val). The isolation included gel chromatography and solvent (CHCl(3)) extraction; in the case of roasted coffee brews, polyamide column chromatography was also used. The identification was achieved by LC-ESI-MS and -MS/MS by comparison of the retention time and the fragmentation pattern with reference compounds. As a second method GC-EI-MS was used. By both methods the presence of diketopiperazines in roasted coffee was unambiguously verified.
authors.affiliation: Institut für Lebensmittelchemie, Technische Universität Braunschweig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ginz
authors.forename: U H
authors.initials: UH
authors.lastname: Engelhardt
mesh_terms: D003069:Coffee / Q000737:chemistry*; D054659:Diketopiperazines; D013058:Mass Spectrometry / Q000379:methods; D010879:Piperazines / Q000032:analysis*; D011392:Proline / Q000737:chemistry*
chemical_list: D003069:Coffee; D054659:Diketopiperazines; D010879:Piperazines; D011392:Proline