The effect of different filter aid materials and winterization periods on the oxidative stability of sunflower and corn oils

The effects of different filter aid materials at different ratios (0.3% or 0.6%, w/w) and three different (6h, 12h, 24h) winterization times, on free fatty acid (FFA), peroxide, iodine, p-anisidine and conjugated diene values and copper (Cu), iron (Fe), nickel (Ni) levels of sunflower and corn oils were studied. FFA amounts of both sunflower and corn oils showed no significant changes during winterization process. However, peroxide, p-anisidine and conjugated diene values increased during winterization due to the holding time in winterized tank and atmospheric conditions. Iodine values of oils increased as unsaturation rises. In respect of trace metals, the increase in copper and iron levels was found higher than the increase of nickel level.