DIN EN ISO 3960:2017-05

This International Standard specifies a method for the iodometric determination of the peroxide value of animal and vegetable fats and oils with a visual endpoint detection. The peroxide value is a measure of the amount of oxygen chemically bound to an oil or fat as peroxides, particularly hydroperoxides. The method is applicable to all animal and vegetable fats and oils, fatty acids and their mixtures with peroxide values from 0 meq to 30 meq (milliequivalents) of active oxygen per kilogram. It is also applicable to margarines and fat spreads with varying water content. The method is not suitable for milk fats and is not applicable to lecithins. It is to be noted that the peroxide value is a dynamic parameter, whose value is dependent upon the history of the sample. Furthermore, the determination of the peroxide value is a highly empirical procedure and the value obtained depends on the sample mass. It is stressed that, due to the prescribed sample mass, the peroxide values obtained can be slightly lower than those obtained with a lower sample mass. Milk and milk products (or fat coming from milk and milk products) are excluded from the scope of this International Standard. The test sample is dissolved in isooctane and glacial acetic acid, and potassium iodide is added. The iodine liberated by the peroxides is determined iodometrically (visually) with a starch indicator and a sodium thiosulfate standard solution. The endpoint of the titration is determined iodometrically (visually). The International Standard has been prepared by ISO/TC 34/SC 11 "Animal and vegetable fats and oils" (secretariat: BSI, United Kingdom) of Technical Committee ISO/TC 34 "Food products" (secretariat: AFNOR, France). CEN/TC 307 "Oilseeds, vegetable and animal fats and oils and their by-products - Sampling and test methods" (secretariat: AFNOR, France) is responsible for the European Standard. On the national level, NA 057-05-05 AA "Gemeinschaftsausschuss für die Analytik von Fetten, Ölen, Fettprodukten, verwandten Stoffen und Rohstoffen" (GA Fett) ("Joint Committee for the analysis of fats, oil, fat products, related substances and raw materials") of the German Society for Fat Science (DGF) and DIN Standards Committee Food and Agricultural Products (NAL) is responsible for the standard.