A study of the determination of peroxides in fats

Summary The Kokatnur‐Jelling method as modified by Lingenfelter for the determination of peroxides in animal fat has been found to agree satisfactorily with other methods now in use. The modified method involves a microtitration in a homogeneous medium (isopropanol) and has the additional advantages of being both simple and rapid. A statistical analysis of the peroxide values shows that the reaction time and temperature and the sample size must be standardized to obtain reproducible and reliable results. Close adherence to reaction specifications such as five minutes at 80°C. or seven minutes at 75°C. is necessary. Three minutes is too short a reaction time. The individual fat sample should contain no more than 50 microequivalents of peroxygen to avoid depression of the peroxide value.