Antioxygenic properties of molecularly distilled fractions of peanut oil

Summary 1. Samples of unhydrogenated and hydrogenated peanut oils, which had been refined, bleached, and deodorized, were separated into two comparable series of fractions by molecular distillation. The various fractions were analyzed for tocopherols (and related chromogens) by the method of Furter and Meyer, and stability tests by the Swift method were made on the larger distilled fractions. 2. Molecular distillation at 140°, 160°, and 180° C. yielded antioxidant concentrates (presumably of tocopherols) from each oil; distillation at 240° yielded fractions almost devoid of antioxygenic substances. 3. In the unhydrogenated and hydrogenated oils, approximately 40 percent and 20 percent, respectively, of the chromogenic substances reacting in the Furter-Meyer tests were undistillable and remained in the residue comprising 10 percent of the original oil. 4. Evidence was found of the presence of distillable antioxidants other than tocopherols, which either do not respond to the Furter-Meyer test or else respond to it weakly, in proportion to their antioxygenic activity. 5. Hydrogenation of the oil had no appreciable effect on the activity of its distillable antioxidants. 6. The progressively increased addition of tocopherol-rich concentrates to fractions almost devoid of antioxidants resulted in first decreasing and then increasing the initial rate of peroxide formation in the stability tests. 7. In the case of the unhydrogenated oil, there was an optimum level of antioxidant concentration above which the addition of these substances had no stabilizing action. However, hydrogenated oil showed an increase in stability with the addition of antioxidants up to the highest level to which the concentration of the latter was carried (approximately 0.15 percent, calculated asa-tocopherol). Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 12 to 14, 1943.