Determination of Toxic α-Dicarbonyl Compounds, Glyoxal, Methylglyoxal, and Diacetyl, Released to the Headspace of Lipid Commodities upon Heat Treatment

Toxic alpha-dicarbonyl compounds, glyoxal, 2-methylglyoxal, and diacetyl, released from the headspace from butter, margarine, safflower oil, beef fat, and cheese heated at 100 and 200 degrees C were analyzed by gas chromatography as quinoxaline derivatives. Total amounts of alpha-dicarbonyl compounds ranged from 40.5 ng/g (butter) to 331.2 ng/g (beef fat) at 100 degrees C and from 302.4 ng/g (safflower oil) to 4521.5 ng/g (margarine) at 200 degrees C. The total amount of alpha-dicarbonyl compounds increased approximately 55- and 15-fold in the headspace of heated butter and margarine, respectively, when the temperature was increased from 100 to 200 degrees C. However, only slight differences associated with temperature variation were observed in the cases of safflower oil and beef fat (1.3- and 1.1-fold, respectively). Diacetyl was found in the highest amounts among all samples, ranging from 13.9 +/- 0.3 ng/g (butter) to 2835.7 ng/g (cheese) at 100 degrees C and from 112.5 +/- 102 ng/g (safflower oil) to 2274.5 +/- 442.6 ng/g (margarine) at 200 degrees C, followed by methylglyoxal, ranging from 13.0 +/- 0.5 to 112.7 +/- 10.1 ng/g (cheese) at 100 degrees C and from 34.7 +/- 5.0 ng/g (safflower oil) to 1790 +/- 372.3 ng/g (margarine) at 200 degrees C. Much less glyoxal formed, in amounts ranging from 13.6 +/- 0.7 ng/g (butter) to 53.4 +/- 11.2 ng/g (beef fat) at both temperatures. The amounts of alpha-dicarbonyl compounds released into the vapor phase from lipid commodities during heating were satisfactorily analyzed.