ISOLATION AND CHARACTERIZATION OF VOLATILE SULFUR-CONTAINING MEAT FLAVOR COMPONENTS IN MODEL SYSTEMS

Reaction of an aqueous solution of cystine with thiamin, glutamate, and ascorbic acid produces a complex mixture of compounds with an overall flavor resembling that of roasted meat. The reaction was carried out at 120 °C for 0.5 h at pH 5.0 in a closed system. The aroma compounds were isolated by means of the simultaneous steam distillation/solvent extraction method according to Likens-Nickerson. The flavor concentrate was preseparated by liquid chromatography on silica gel using a pentane-diethyl ether gradient and subsequently analyzed by GC and GC/MS. Sulfur components were detected by a selective flame photometric detector. Unknown flavor components were isolated by preparative capillary gas chromatography, and the structures were elucidated on the basis of spectroscopic studies. Various heterocyclic thioethers, disulfides, and hemidithioacetals were identified for the first time in the volatiles of the heated meat flavor model mixture. Formation pathways, sensory properties, and spectroscopic data of newly identified flavor components are discussed. In most cases, identifications were confirmed by organic syntheses. Some of the most important mass spectrometric fragmentation pathways are proposed. © 1990, American Chemical Society. All rights reserved.