Retardation of 4-Hydroxy-2-Transnonenal (HNE), a Toxic Aldehyde Formation by Antioxidants in Heat-Treated Corn Oil at Frying Temperature

The antioxidative properties of four antioxidants such as rosemary extracts (RE), tert-butylhydroquinone (TBHQ), ascorbyl palmitate (AP), citric acid (CA) and their mixtures were investigated on the formation of 4-hydroxy-2-transnonenal (HNE) in commercial corn oil heated at 185°C for up to 6 hours. Among the antioxidants 100 ppm RE and a mixture of 200 ppm tertiary butylated hydroquinone (TBHQ) + 100 ppm ascorbyl palmitate (AP) + 50 ppm citric acid (CA) exhibited excellent antioxidative activity, as determined by the thiobarbituric acid reaction (TBARS) assay, measuring the formations of the secondary lipid oxidation products and by high-performance liquid chromatography (HPLC), measuring the formation of the toxic α, β-unsaturated hydroxyaldehyde HNE after heat treatment of corn oil at 185°C up to 6 hours. TBHQ, AP and CA alone did not show much protective properties. The synergistic effects of TBHQ + AP + CA mixture shown to reduce the formation of HNE after 6 hours heat-treated corn oil by 27%. RE 100 ppm was also found to be a very effective antioxidant, reducing the formation of HNE after 6 hours heat-treated corn oil in the same condition by 29%.