Study of polycyclic aromatic hydrocarbons generated from fatty acids by a model system.

BACKGROUND

The characteristics of carcinogenic polycyclic aromatic hydrocarbons (PAHs) produced from various fatty acids, as important components of fats and oils, at high temperature are still little known. The reason is because the existing data are from experiments conducted in complex food systems. In this study, 12 PAHs produced from nine fatty acids, representing saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), were investigated in a model system heated at 98, 165 and 240 °C.

RESULTS

SFAs can with difficulty be pyrolyzed to generate PAHs at 98 °C, but small amounts of PAHs were determined in MUFAs (44.97 µg kg ) and PUFAs (177.73 µg kg ). When the temperature reached 165 °C, there were totals of 27.59, 142.8 and 449.68 µg kg PAHs assayed in SFAs, MUFAs and PUFAs, respectively. The amounts of PAHs generated from SFAs, MUFAs and PUFAs at 240 °C were higher when compared with those of the 165 °C group (P < 0.05). With an increase of heating temperature, the proportion of PAHs with four to five rings increased. Under the same heating conditions, the concentration of PAHs in fatty acids increased with an increase in the number of double bonds.

CONCLUSIONS

More PAHs, especially carcinogenic ones with four to five rings, will be produced in fatty acids heated at higher temperature. The content of PAHs generated from fatty acids increased with an increase in the number of double bonds. This study will increase the understanding of the production characteristics of PAHs from various fatty acids under heating condition. © 2019 Society of Chemical Industry.