Iodine value in rapeseed oil and olive oil – Modified standard method reduces reaction time for faster results

The iodine number is an important sum parameter for assessing the quality of edible fats and oils. It provides quantitative information about the presence of unsaturated fats and oils. The higher the amount of unsaturated fatty acids in the sample, the more iodine reacts with the double bonds, resulting in a higher iodine value. For native oils, such as sunflower or olive oil, the iodine value is well known. Hence, it can be used as a test parameter for counterfeit detection in the fight against food fraud.

For the classical titrimetric determination, the samples have to be placed in the dark for up to 2 hours, after the addition of the reaction solution (Wijs solution). In this Application Note, we describe a modified analysis based on EN ISO 3961, ASTM D5554, AOAC 920.159, AOAC 993.20, AOCS Cd 1d-92, USP<401> Method II, and Ph.Eur. 2.5.4 Method B. For this modified analysis, magnesium acetate is added as catalyst, reducing the reaction time from up to 2 h to 5 min. This modified analysis thus allows a much higher productivity in the lab.