RECOGNITION OF ADULTERATED OILS BY DIRECT ANALYSIS OF THE MINOR COMPONENTS

Recognition of adulteration by other oils via direct analysis of the m inor components (''sterol fraction'') is shown for olive oil. 10% of v arious oils were admixed, the free alcohols silylated and the minor co mponents analyzed by on-line coupled LC-GC-FID. For most oils, even sm aller additions can be recognized. Admixed oils can no longer be deter mined, however, if their minor components have been removed by strong raffination. Bleaching of rapeseed oil with 7% of earth at 180-degrees -C, in fact, completely removed free and esterified sterols.