Matrix-mediated distribution of 4-hydroxy-2-hexanal (nonenal) during deep-frying of chicken breast and potato sticks in vegetable oil

In this study, the formation of two toxic reactive aldehydes, 4-hydroxy-2-hexenal and 4-hydroxy-2-nonenal, was investigated during frying two different foodstuffs at 180 °C for 7h in three different vegetable oils. Results showed that HHE and HNE content in oil after frying was lower than that in oil fried without foods. It was mainly because of the incorporation of HHE/HNE into fried food. In French fries (FF) HNE content was higher, whereas lower in fried chicken breast meat (FCBM). The bidirectional model systems consisted of model oil frying system and model food frying system were conducted. Result of model oil system showed that content of HNE was higher in FF for the higher hydrophobic property than HHE which would be preferred bounded into the hydrophobic helical structures, whereas lower content of HNE was observed in FCBM for its higher reactivity towards the nucleophilic group, namely protein in FCBM. Furthermore, model food frying system including starch and protein extracted from the corresponding foodstuffs verified the results in model oil system. Finally, the probable migration mechanism of HHE and HNE in different food matrixes was proposed for the first time.