title: Quantitative Model Studies on the Effectiveness of Different Precursor Systems in the Formation of the Intense Food Odorants 2-Furfurylthiol and 2-Methyl-3-furanthiol.
abstract: The yields of the two intense food odorants 2-furfurylthiol (FFT) and 2-methyl-3-furanthiol (MFT) obtained by heating mixtures of possible precursors in model systems varying in temperature, pH value, or water content were determined by using stable isotope dilution assays. Although pentoses generated much higher amounts of FFT and MFT than hexoses when heated in the presence of cysteine, glucose and rhamnose also gave significant yields. Studies on several intermediates indicated the highest yields for MFT (1.4 mol %) when hydroxyacetaldehyde and mercapto-2-propanone were reacted for 6 min at 180 degrees C in the absence of water. Both intermediates also generated significant amounts of FFT (0.05 mol %). However, the system furan-2-aldehyde/H(2)S showed a 10 times higher efficiency in generating FFT. Thiamin and norfuraneol/cysteine were less effective precursors of MFT. The results imply that different formation pathways may run in parallel during food processing and may account for the different amounts of the two odorants present in the respective food.
authors.affiliation: Deutsche Forschungsanstalt für Lebensmittelchemie, Lichtenbergstrasse 4, D-85748 Garching, Germany.
authors.initials: T
authors.lastname: Hofmann
authors.initials: P
authors.lastname: Schieberle