The temperature dependence of the formation of toxic 4-hydroxy-2-trans-nonenal (HNE) was investigated in high and low linoleic acid (LA) containing oils such as corn, soybean and butter oils.
These oils contain about 60, 54 and 3–4% of LA for corn, soybean and butter oils, respectively. The oils were heated for 0,
0.5, 1, 2, and 3h at 190°C and for 0, 5, 15 and 30min at 218°C. HNE concentrations in the oils were analyzed by high performance
liquid chromatography (HPLC). The maximum HNE concentrations in heated (190°C) corn, soybean and butter oils were 5.46, 3.73
and 1.85μg HNE/g oil, respectively. The concentration of HNE at 218°C increased continuously for all the three oils, although
they were heated for much shorter periods compared to the lower temperature of heating (190°C). HNE concentration at 30min
reached the maximum of 15.48, 10.72 and 6.71μg HNE/g oil for corn, soybean and butter oils, respectively. HNE concentration
at higher temperature (218°C) was 4.9, 3.7, and 8.7 times higher than at the lower temperature (190°C) and 30min of heating
for corn, soybean and butter oils, respectively. It was found that HNE formation was temperature dependant in the tested oils.