Rapid, sensitive, iron-based spectrophotometric methods for determination of peroxide values of food lipids.

The official International Dairy Federation method for determination of the peroxide value of anhydrous milk fat was extended to poultry, meat, fish, and vegetable oils. The ferrous oxidation-xylenol orange method for determination of peroxide values of liposomes and lipoproteins was modified to make it simpler and more rapid. These 2 spectrophotometric methods were used successfully to determine the peroxide values of beef, chicken, butter, fish, and vegetable products. The results in most cases were consistent with those obtained by using the AOAC Official Method. The spectrophotometric methods have an assay time of less than 10 min, require < or = 0.3 g fat, and are capable of determining peroxide values as low as 0.1 mequiv/kg of sample.