DETERMINATION OF RAFFINATION OF EDIBLE OILS AND FATS BY OLEFINIC DEGRADATION PRODUCTS OF STEROLS AND SQUALENE, USING COUPLED LC-GC

Raffination of edible oils and fats, i.e. bleaching with earth or charcoal as well as deodoration, can be determined by the analysis of dehydroxylation products of sterol, and isomerization products of squalene. These olefinic degradation products are isolated from the rest of the oil by LC on silica gel and on-line transfer to GC. Sample preparation consists of preparing a 20 % solution of the oil. Nearly half of the "extra virgin" olive oils analyzed contained such products, but concentrations were too low for assuming admixture of regularly refined oils. However, many other oils advertized as non-refined turned out to have been treated beyond declaration.