Autoxidation of Methyl Linoleate in Freeze‐Dried Model Systems. I. Effect of Water on the Autocatalyzed Oxidation

Abstract

SUMMARY Oxidation of methyl linoleate was studied in a freeze‐dried model system based on micro‐crystalline cellulose. Oxidation was followed manometrically in samples adjusted to various water activities ranging from approximately 0 to approximately 0.6. Water was found (as determined from induction period and rate data) to have an inhibitory effect on the oxidation reaction, varying with water activity up to values of 0.5. Evaluation of the rate data indicates that the inhibitory effect of water is most pronounced in the initial stages of oxidation, including the period during which the hydroperoxide decomposition follows monomolecular decomposition kinetics. Possible interpretations of the observed water effect and its significance to the general problem of lipid oxidation in dehydrated foods are discussed.