A spectrophotometric assay for lipid peroxides in serum lipoproteins using a commercially available reagent.

Mechanisms for the autoxidation of polyunsaturated lipids

An alkyl hydroperoxide reductase from Salmonella typhimurium involved in the defense of DNA against oxidative damage. Purification and properties.

Oleic, linoleic and linolenic acids were autoxidized more rapidly than their corresponding methyl esters. Addition of stearic acid accelerated the rate of autoxidation of methyl linoleate and the decomposition of methyl linoleate hydroperoxides. Therefore, the higher oxidative rate of FFA’s than their methyl esters could be due to the catalytic effect of the carboxyl groups on the formation of free radicals by the decomposition of hydroperoxides. Addition of stearic acid also accelerated the oxidative rate of soybean oil. This result suggests that particular attention should be paid to the FFA content that affects the oxidative stability of oils.

Study on the oxidative rate and prooxidant activity of free fatty acids

Effect of different cooking methods on some lipid and protein components of hamburgers.

Improved procedures of the Swoboda and Lea method for the determination of peroxide values (POV) of fats and lipids are presented. After oxidation of iodide to iodine with the sample for 5 min under an inert atmosphere, an excess of the iodide ion is immediately converted to cadmium complex for protection from atmospheric oxygen. The iodine is measured colorimetrically at 358 or 410 nm, and POV is calculated from the absorbance. This method permits the rapid determination of POV with a small amount of sample at a moderate cost using usual glasswares. For the analysis of lipids in biological materials or food products, the chloroform solution obtained by the Bligh and Dyer method is directly subjected to this procedure without evaporation of the solvent. Conversions between POV obtained by the different methods are discussed.

Yuichiro Mitsuno

Papers

Determination of peroxide value by the colorimetric iodine method with protection of iodide as cadmium complex