Performance of some edible oils during heating in a steam pressure cooker

The performance of corn, soybean and hazelnut oils was investigated over a 60-min period in a steam pressure cooker at 121C and 1.1 atm pressure. These conditions are typical of Turkish domestic cooking. In this study, the oxidative stability of the three oils was compared using peroxide value (PV), conjugated diene (CD) value and free fatty acid (FFA) content. Fatty acid composition of oils was also determined. Heating of oils for 60 min caused a significant increase in peroxide value (P < 0.05), but PV of hazelnut oil was lower than those of soybean and corn oils (P < 0.05). FFA and CD values of soybean and hazelnut oils showed an insignificant increase (P > 0.05), while the increase in corn oil was significant (P < 0.05). Minor differences existed between the fatty acids, except for linolenic acid, at the begining and at the end of the process.