title: Real-time monitoring of 4-vinylguaiacol, guaiacol, and phenol during coffee roasting by resonant laser ionization time-of-flight mass spectrometry.
abstract: The formation of 4-vinylguaiacol, guaiacol, and phenol during coffee roasting was monitored in real-time, using resonance enhanced multiphoton ionization and time-of-flight mass spectrometry. A model is proposed, based on two connected reaction channels. One channel, termed the "low activation energy" channel, consists of ester hydrolysis of 5-FQA followed by decarboxylation of the ferulic acid to form 4-vinylguaiacol, and finally polymerization at the vinyl group to form partly insoluble polymers (coffee melanoidins). The second "high activation energy" channel opens up once the beans have reached higher temperatures. It leads to formation of guaiacol, via oxidation of 4-vinylguaiacol, and subsequently to phenol and other phenolic VOCs. This work aims at developing strategies to modify the composition of coffee flavor compounds based on the time-temperature history during roasting.
authors.affiliation: GSF, National Research Center for Environment and Health, Institute of Ecological Chemistry, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Dorfner
authors.forename: Thomas
authors.initials: T
authors.lastname: Ferge
authors.forename: Antonius
authors.initials: A
authors.lastname: Kettrup
authors.forename: Ralf
authors.initials: R
authors.lastname: Zimmermann
authors.forename: Chahan
authors.initials: C
authors.lastname: Yeretzian
mesh_terms: D040503:Coffea / Q000737:chemistry*; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000032:analysis*; D006358:Hot Temperature; D013058:Mass Spectrometry / Q000379:methods; D019800:Phenol / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*
chemical_list: D019800:Phenol; D006139:Guaiacol; C014245:4-vinylguaiacol