Effect of heating on the oxidative stability of corn oil and soybean oil

The effects of conventional and microwave heating on the oxidative properties of corn and soybean oil were evaluated. The results showed that acid value, peroxide value, oxidative indices, total oxidation value, and p-anisidine values changed significantly with the rise in temperature (p < 0.05). The peroxide and p-anisidine values for corn oil (PV: 50.670 meqO2/kg, p-AV: 8.248) were greater than soybean oil (PV: 41.694 meqO2/kg, p-AV: 7.566) for conventional heating. The peroxide and p-anisidine values for soybean oil (PV: 6.545 meqO2/kg, p-AV: 76.539) were greater compared to corn oil (PV: 5.074 meqO2/kg, p-AV: 65.360) for microwave heating. The results concluded that microwave heating had a greater impact on the chemical degradation of the fatty acids of the oil. The FT-IR spectra showed peak changes at 3743 cm-1 and 1739 cm-1 and confirmed the rancidity of the oils from microwave heating due to the formation of secondary oxidation products. It was concluded that corn oil showed more oxidative changes compared to soybean oil.