In Situ Preparation of Fatty Acid Methyl Esters for Analysis of Fatty Acid Composition in Foods

Abstract

ABSTRACT Lipid extraction preceding fatty acid methyl esters (FAME) preparation for gas chromatography is time‐consuming and cumbersome. We omitted the lipid extraction and performed in situ transesterification (ISTE) by heating lipid‐containing foods at 90°for 10 min after adding 0.5N NaOH in methanol for methanolysis and continued heating another 10 min for further methylation after adding 14% BF 3 in methanol. FAME prepared by ISTE showed fatty acid composition virtually identical to FAME prepared after lipid extraction from powder, liquid, phospholipid‐rich, and tissue products. Due to its simplicity, speed, and reduced organic solvent usage, ISTE should be useful to determine overall fatty acid composition of foods.