Effect of roasting on the chemical components of peanut oil

The chemical components and oxidative stability of oil prepared from roasted peanut kernels in dry air were investigated and compared with those prepared from unroasted peanut oil in relation to health-promoting and harmful substances (trans-fatty acid, TFA). During roasting, the acid value (AV) of the peanut oils from roasted kernels ranged between 0.35 and 0.69 mg KOH/g. Tocopherol, squalene, and TFAs (including elaidic, linoelaidic and linolelaidic acids) in peanut oil increased with increased roasting temperature or time. Under all roasting conditions, the TFAs accounted for <0.2% of the total FA. PV decreased to ≤5 mmol/kg at 180 °C–190 °C for 20–30 min and at 170 °C for 25–30 min. The FA composition and triacylglycerol profile had no evident differences during roasting. The oxidative stability of peanut oil increased with increased roasting temperature or time. Therefore, the favorable sensory qualities and beneficial healthy components of peanut oil may be attributed to the treatment by roasting at 170 °C for 20–30 min or at 180 °C–190 °C for 25–30 min.