title: Taste-Active Maillard Reaction Products in Roasted Garlic (Allium sativum).
abstract: In order to gain first insight into candidate Maillard reaction products formed upon thermal processing of garlic, mixtures of glucose and S-allyl-l-cysteine, the major sulfur-containing amino acid in garlic, were low-moisture heated, and nine major reaction products were isolated. LC-TOF-MS, 1D/2D NMR, and CD spectroscopy led to their identification as acortatarin A (1), pollenopyrroside A (2), epi-acortatarin A (3), xylapyrroside A (4), 5-hydroxymethyl-1-[(5-hydroxymethyl-2-furanyl)methyl]-1H-pyrrole-2-carbalde-hyde (5), 3-(allylthio)-2-(2-formyl-5-hydroxymethyl-1H-pyrrol-1-yl)propanoic acid (6), (4S)-4-(allylthiomethyl)-3,4-dihydro-3-oxo-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (7), (2R)-3-(allylthio)-2-[(4R)-4-(allylthiomethyl)-6-formyl-3-oxo-3,4-dihydropyrrolo-[1,2-a]pyrazin-2(1H)-yl]propanoic acid (8), and (2R)-3-(allylthio)-2-((4S)-4-(allylthiomethyl)-6-formyl-3-oxo-3,4-dihydropyrrolo-[1,2-a]pyrazin-2(1H)-yl)propanoic acid (9). Among the Maillard reaction products identified, compounds 5-9 have not previously been published. The thermal generation of the literature known spiroalkaloids 1-4 is reported for the first time. Sensory analysis revealed a bitter taste with thresholds between 0.5 and 785 μmol/kg for 1-5 and 7-9. Compound 6 did not show any intrinsic taste (water) but exhibited a strong mouthfullness (kokumi) enhancing activity above 186 μmol/kg. LC-MS/MS analysis showed 1-9 to be generated upon pan-frying of garlic with the highest concentration of 793.7 μmol/kg found for 6, thus exceeding its kokumi threshold by a factor of 4 and giving evidence for its potential taste modulation activity in processed garlic preparations.
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Straße 34, D-85354 Freising, Germany.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Wakamatsu
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Straße 34, D-85354 Freising, Germany.
authors.forename: Timo D
authors.initials: TD
authors.lastname: Stark
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Straße 34, D-85354 Freising, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hofmann
mesh_terms: D000328:Adult; D003296:Cooking; D005260:Female; D005421:Flavoring Agents / Q000737:chemistry*; D005737:Garlic / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure; D013649:Taste
chemical_list: D005421:Flavoring Agents
keywords: Maillard reaction; S-allyl-l-cysteine; garlic; kokumi; taste