Effect of frying and aluminium on the levels and migration of parent and oxygenated PAHs in a popular Chinese fried bread youtiao.

This study investigated the effects of frying conditions on the change, migration and correlation of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (oxy-PAHs) in youtiao, a typical Chinese fried bread. PAH migration was evaluated using an isotope tracer method. High concentrations of oxy-PAHs, especially 9-fluorenone (1.75μg/kg) and anthracene-9,10-dione (6.41μg/kg), were detected. The results revealed that 1) prolonged continuous frying decreased parent PAH and oxy-PAH concentrations, 2) frying temperature and aluminium content did not have significant effects on parent PAH concentrations, 3) PAH migration rates (2.02-18.48%) varied significantly based on the frying oil type, and 4) the sum of five oxy-PAH concentrations was significantly correlated with the sum of 16 parent PAH concentrations in soybean oil-fried youtiao. Three oxy-PAHs (9-fluorenone, anthracene-9,10-dione, and 9,10-dihydrobenzo[a]pyren-7(8h)-one) were significantly correlated with their respective parent PAHs. The results might be helpful for further study and evaluation on oxy-PAHs and PAHs in fried foods.