DIN EN ISO 12966-3:2016-11

This International Standard specifies a rapid base-catalysed transesterification method for fats and oils with trimethylsulfonium hydroxide (TMSH) to prepare fatty acid methyl esters. The method is exclusively applicable to the preparation of methyl esters of fats and oils for gas liquid chromatographic (GLC) analysis. It is applicable to all fats and oils, but excluding those coming from milk and milk products. Isomerization of unsaturated fatty acids only occurs to a minor extent and isomerized fatty acids are only present at the determination limit. As isomerization takes place, the procedure is not recommended for conjugated linoleic acid (CLA). Only about 70 % to 80 % of the free fatty acids are esterified. In the case of conjugated cyclopropyl and cyclopropenyl fatty acids, side reactions may occur, but these do not interfere with the determination of the fatty acids. 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). The responsible body for the European Standard is CEN/TC 307 "Oil seeds, vegetable and animal fats and oils and their by-products - Methods of sampling and analysis" (secretariat: AFNOR, France). On the national level, the standard is supervised by NA 057-05-05 AA "Gemeinschaftsausschuss für die Analytik von fetten, Ölen, Fettprodukten, verwandten Stoffen und Rohstoffen" (GA Fett) of the German Fat Research Society (DGF) ("Joint committee for the analysis of fats, oils and products thereof, related and primary products") and DIN Standards Committee Food and Agricultural Products (NAL)