Determination of degree of oxidation of methyl linoleate and linolenate by weighing method

• Published in: Journal of the American Oil Chemists' Society Vol. 80; no. 6; pp. 591 - 593
• Main Authors: Matikainen, Jorma, Laantera, Matti, Kaltia, Seppo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-06-2003; Springer
• Subjects: Biological and medical sciences; Fat industries; Food industries; Fundamental and applied biological sciences. Psychology; Linoleate; linolenate; weighing method and oxidation; Autoxidation; Linolenic acid; Polyunsaturated fatty acid; Lipids; Oxidation; Measurement method; linolenate; Fatty acid methyl ester; Photooxidation; weighing method and oxidation; Linoleate; Linoleic acid
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-003-0743-8

Autoxidation of methyl linolenate and linoleate was investigated at room temperature in the light and dark during a period of 2 mon using a weighing method accompanied with 1H NMR measurements. In the light, the increase in weight, or autoxidation process, of the two compounds began immediately after the start of the experiment. In the dark, the weight of methyl linolenate began to increase after a delay of 1 wk, and the weight of methyl linoleate after 40 d. The maximal increases in the weights of the compounds were somewhat greater in the dark than in the light; the weight of methyl linolenate in the dark increased by 22.3% and in the light by 20.8%. The corresponding values for methyl linoleate were 16.9 and 14.4%, respectively. Results of the NMR measurements were compared to the weighing results, and a table was constructed representing the correlation between selected multiplets and corresponding weight increments.