title: Quantitative studies on roast kinetics for bioactives in coffee.
abstract: Quantitative analysis of the bioactives trigonelline (1), N-methylpyridinium (2), caffeine (3), and caffeoylquinic acids (4) in a large set of roasted Arabica (total sample size n = 113) and Robusta coffees (total sample size n = 38) revealed that the concentrations of 1 and 4 significantly correlated with the roasting color (P < 0.001, two tailed), whereas that of 2 significantly correlated inversely with the color (P < 0.001, two tailed). As dark-roasted coffees were rich in N-methylpyridinium whereas light-roasted coffees were rich in trigonelline and caffeoylquinic acids, manufacturing of roast coffees rich in all four bioactives would therefore necessitate blending of two or even more coffees of different roasting colors. Additional experiments on the migration rates during coffee brewing showed that all four bioactives were nearly quantitatively extracted in the brew (>90%) when a water volume/coffee powder ratio of >16 was used.
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Straße 34, D-85354 Freising, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Lang
authors.forename: Erkan Firat
authors.initials: EF
authors.lastname: Yagar
authors.forename: Anika
authors.initials: A
authors.lastname: Wahl
authors.forename: Anja
authors.initials: A
authors.lastname: Beusch
authors.forename: Andreas
authors.initials: A
authors.lastname: Dunkel
authors.forename: Natalie
authors.initials: N
authors.lastname: Dieminger
authors.forename: Rudolf
authors.initials: R
authors.lastname: Eggers
authors.forename: Gerhard
authors.initials: G
authors.lastname: Bytof
authors.forename: Herbert
authors.initials: H
authors.lastname: Stiebitz
authors.forename: Ingo
authors.initials: I
authors.lastname: Lantz
authors.forename: Thomas
authors.initials: T
authors.lastname: Hofmann
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D002110:Caffeine / Q000737:chemistry*; D040503:Coffea / Q000737:chemistry*; D003296:Cooking; D007700:Kinetics; D011726:Pyridinium Compounds / Q000737:chemistry*; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D012639:Seeds / Q000737:chemistry
chemical_list: D000470:Alkaloids; D011726:Pyridinium Compounds; C472707:caffeoylquinic acid; D011801:Quinic Acid; D002110:Caffeine; C009560:trigonelline; C014677:1-methylpyridinium