LAUSR

Abstract Trans fatty acid (TFA) content in foods is not regulated in most European countries. Fatty acid (FA) composition, total TFA levels, and TFA isomers were determined for 43 margarines available on the Slovenian market and 33 samples of shortenings used by food manufacturers. In most margarines, the TFA content (as a percentage of total FA) was low (0.1–0.8%), although two different margarines contained 3.1% and 6.4% TFA, respectively. In shortenings, a wider variation in TFA content (from 0.1% to 11.2%) was observed. In samples with high total TFA, trans-C18:1 was present in higher quantities than trans-C18:2 and trans-C18:3. In almost all samples, the predominant TFA isomers were elaidic acid (t9-C18:1) and t10-C18:1, followed by t11-C18:1 and (t6-t8)-C18:1. Isomers t12-C18:1 and (t13-t14)-C18:1 were also detected. Among trans-C18:2 isomers the t/c-C18:2 predominated over c/t-C18:2 and t/t-C18:2. Above 2% TFA was only found in samples labelled to contain partially hydrogenated fats. Results show a high variability in the FA composition of hard vegetable fats in the food supply, and indicate that more efficient regulation and control on the market are needed to minimize the exposure of the population to TFAs.