Abstract
For determination of low peroxide values (POV) of lipids, the JOCS method was modified by the employment of a potentiometer instead of starch as an indicator.
This method required only 0.02 g of lipids to determine POV when POV is higher than 1 meq/kg, and 0.1 g of lipids when that is lower than 1 meq/kg. As it was found that chloroform could be replaced by the Folch solvent (Chloroform : Methanol = 2 : 1) in the determination, the amount of per-oxides of lipids occuring in biological samples was measured with the latter solvent, so that there was no need of solvent removal after extraction.
As compared with the thiobarbituric acid test which reads the quantity of malonaldehyde, one of the decomposed products of peroxides, an advantage of the present method is that a small amount of peroxides which are the first products at the initial stage of oxidation of lipids can be determined directly, while the amount of malonaldehyde is less than that of the peroxides at the stage and not always proportional to the degree of oxidation of mother lipids.
