title: Taste modulating N-(1-methyl-4-oxoimidazolidin-2-ylidene) α-amino acids formed from creatinine and reducing carbohydrates.
abstract: Recent investigations led to the discovery of N-(1-methyl-4-oxoimidazolidin-2-ylidene)aminopropionic acid as a taste modulator enhancing the typical thick-sour mouthdryness and mouthfulness imparted by stewed beef juice. In the present study, systematic model reactions were targeted toward the generation of a series of N-(1-methyl-4-oxoimidazolidin-2-ylidene)-α-amino acids by Maillard-type reactions between creatinine and ribose, glucose, methylglyoxal, or glyoxal, respectively. By application of a comparative taste dilution analysis on fractions isolated from thermally treated creatinine/carbohydrate mixtures by means of hydrophilic liquid interaction chromatography (HILIC), a total of nine N-(1-methyl-4-oxoimidazolidin-2-ylidene)-α-amino acids were identified by means of LC-MS, LC-TOF-MS, and 1D/2D NMR experiments. Six of the nine creatinine glycation products were previously not reported in the literature. Whereas creatinine exhibited a bitter taste, none of the N-(1-methyl-4-oxoimidazolidin-2-ylidene)-α-amino acids imparted any intrinsic taste activity up to levels of 10 mmol/L (in water). Depending strongly on their chemical structure, these N-(1-methyl-4-oxoimidazolidin-2-ylidene)-α-amino acids induced a thick-sour, mouthdrying orosensation and mouthfulness enhancement when evaluated in model broth with recognition thresholds ranging from 31 to >1000 μmol/L.
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Freising, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Kunert
authors.forename: Alesia
authors.initials: A
authors.lastname: Walker
authors.forename: Thomas
authors.initials: T
authors.lastname: Hofmann
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry*; D003404:Creatinine / Q000737:chemistry*; D005260:Female; D006801:Humans; D015416:Maillard Reaction; D008297:Male; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013649:Taste; D055815:Young Adult
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D003404:Creatinine