Evaluation of the non-aldehyde volatile compounds formed during deep-fat frying process.

To investigate the non-aldehyde volatile profile resulting from deep-fat frying, volatile compounds formed during the processes of heating soybean oil (SO), frying wheat dough (WD), and frying chicken breast meat (CBM) were comparatively studied. By using gas chromatography-mass spectrometry and internal standard method, alkanes, alkenes, alkynes, alcohols, ketones, nitrogen-containing volatiles (NCVs), and other volatiles were qualitatively and relatively quantitatively detected. NCVs were detected only in CBM-fried oil samples. Some volatiles (e.g. 2-pentylfuran and 2-pentylpyridine) were observed to increase in concentration, whereas others (e.g. 4-methyl-1,4-heptadiene and 7-methyl-3,4-octadiene) were observed to first increase and then decrease in concentration as the heating or frying time increased. Reduced quantity and concentrations of volatiles were observed in the food-fried oil samples which might be related to the intensified reactions induced by food components. The detection of some harmful volatiles in considerable concentrations indicated further attention might be paid to the safety of deep-fat frying.