Analysis of α-dicarbonyl compounds and volatiles formed in Maillard reaction model systems

In this study, production of three alpha-dicarbonyl compounds (alpha-DCs) including glyoxal (GO), methylglyoxal (MGO), and diacetyl (DA) as well as volatile flavor compounds was analyzed using Maillard reaction (MR) model systems. A total of 16 model systems were assembled using four amino acids and four reducing sugars, and reactions were performed at 160 degrees C and pH 9. Determination of alpha-DCs was conducted using a gas chromatography/nitrogen phosphorous detector (GC-NPD) after derivatization and liquid-liquid extraction. alpha-DC levels in MR model systems were 5.92 to 39.10 mu g/mL of GO, 3.66 to 151.88 mu g/ml of MGO, and 1.10 to 6.12 mu g/mL of DA. The highest concentration of total a-DCs was found in the fructose-threonine model system and the lowest concentration in the lactose-cysteine model system. Volatile flavor compounds were analyzed using solid-phase microextraction (SPME) followed by GC-mass spectrometry (GC-MS). Different volatile flavor compound profiles were identified in the different MR model systems. Higher concentrations of alpha-DCs and volatile flavor compounds were observed in monosaccharide-amino acid MR model systems compared with disaccharide-amino acid model systems.