摘要：In order to investigate the atomospheric oxidation of linoleic acid, which generally offers the important factor for the rancidity of edible fats, we tried to oxidize pure methyl linoleate by passing oxygen at 110°. On each sample obtained at the interval of 1-2 hours during oxidation, several chemical constants such as peroxide value (P.O.V.), carbonyl value (Car.V.), acid value (A.V.), dinitrophenylhydrazine value (D.N.P.V.), thiobarbituric acid value (T.B.A.V.), refractive index (R.I.), and iodine value (I.V.) were measured. Moreover, the changes of UV and IR absorption spectra, and gas chromatograph on these samples were examined. The results obtained were as follows : methyl linoleate at first turned into trans-trans conjugated diene, hydroperoxide was formed in this high temperature oxidizing condition, then carbonyl compounds were produced, and carboxylic acids and polymeric compounds increased gradually. Besides the antioxidation effect by the addition of BHA (concentration of 0.1, 0.2%), and synergetic effect of citric acid (0.2%) were observed in this oxidation condition. Though the above mentioned condition is rather convenient for the observation of the effect of antioxidants in a short time, it is too violent to expect precise reproducibility with some chemical constants such as P.O.V. or D.N.P.V.
