Lecithin Near Its Critical Micelle Concentration Increases Oxidative Stability of Non-Stripped Corn Oil But Not Stripped Corn Oil

Effects of lecithin (HLB 4.5) on oxidative stability of non-stripped or stripped corn oil are determined during storage at 50 degrees C. Headspace oxygen content of non-stripped corn oil containing lecithin decreased less with the increasing concentration of lecithin (300-3000 ppm). Lecithin-supplemented non-stripped corn oil near and above critical micelle concentration (CMC, 1288 ppm) had higher oxidative stability as compared to other samples according to conjugated dienoic acid and p-anisidine value assays. Antioxidant and tocopherol concentrations in non-stripped corn oil samples containing lecithin near CMC are found to be the highest. Stripped corn oil has CMC of 1790 ppm lecithin and 600 ppm lecithin shows higher antioxidant properties than other concentration of lecithin from 1200 to 3000 ppm. Presence of phospholipids affected oxidative stability of bulk oils. Non-stripped corn oil supplemented with lecithin near CMC shows the highest oxidative stability, which could be due to the incorporation of tocopherols into the association colloids formed by the added lecithin. Practical Application: Controlling rate of lipid oxidation in bulk oils is one of the important topics in lipid science. Addition of commercially available lecithin (HLB 4.5) could enhance the oxidative stability in non-stripped corn oil especially, at the concentration of lecithin near CMC. Presence of phospholipids affected oxidative stability of bulk oils. By using knowledge shown in this study, food industries could save costs by optimizing the lecithin concentration in bulk oils, which could be used as ingredients of many processed foods. Addition of commercially available lecithin enhances oxidative stability in non-stripped corn oil. Lecithin near or over its critical micelle concentration shows higher antioxidant activity in non-stripped oil compared to other concentrations of lecithin. Added lecithin increases tocopherol stability, especially alpha-tocopherol in non-stripped bulk oil during storage. For stripped corn oil, 600 ppm lecithin only shows some antioxidant power and other concentrations do not enhance oxidative stability.