Studies on the Formation and Stability of the Roast-Flavor Compound 2-Acetyl-2-thiazoline

Article abstract of DOI:10.1021/jf00059a032

2-(1-Hydroxyethyl)-4,5-dihydrothiazole (HDT) was identified by 1H- and 13C-NMR measurements as the main volatile product formed by storage of an aqueous solution of cysteamine and methylglyoxal at low temperatures (6 deg C).The structure of HDT was confirmed by synthesis.Systematic studies on the thermal stability of the HDT under different conditions either in aqueous solution or during high-resolution gas chromatography revealed that HDT is an important intermediate in the formation of the intensely roasty smelling food flavor compound 2-acetyl-2-thiazoline (AT).Model studies showed that more than 10percent of the precursor HDT was converted into AT simply by heating for 10 min in water.The activation energy of this reaction was 57.4 kJ/mol.Experiments on the thermal stability of AT itself revealed that heating in aqueous solution also led to a degradation of AT, whereas heating in an oil significantly stabilized the flavor compound. - Keywords: 2-(1-Hydroxyethyl)-4,5-dihydrothiazole; 2-acetyl-2-thiazoline; flavor precursor; stable isotope dilution analysis.