The anisidine value is a measure of the secondary reaction products that occur during lipid oxidation and in many respects is a more robust indicator of the quality of the oil and the extent of oxidation as the secondary reaction products such as aldehydes and ketones are much more stable in the oil.
The anisidine value is determined as the absorbance of a solution resulting from the reaction of 1g fat in 100ml of isooctane solvent and reagent (0.25% anisidine and glacial acetic acid).