Effects of relative humidity and neutral emulsifier on oxidative stability of corn oil during room temperature storage

The effects of tween 20, one of neutral emulsifiers, on oxidative stability of corn oil were determined under a relative humidity (RH) range of 0–93 % at room temperature after 350 days of storage. The degree of oxidation was determined by headspace oxygen content and conjugated dienoic acids analyses. Moisture content and α-tocopherol were also analyzed. The degree of lipid oxidation was significantly influenced by the concentration of tween 20 and relative humidity. Samples without addition of tween 20 showed the highest oxidative stability in 11 % RH, whereas oxidative stability was lowest at 93 % RH. Adding 0.5 and 1.0 % tween 20 increased the rate of lipid oxidation in a concentration dependent manner. Samples containing tween 20 had higher moisture content than those without an amphiphilic compound. Stability of α-tocopherol was depending on the content of moisture and amphiphilic compounds in bulk oil.