Effect of phenolic extracts on trans fatty acid formation during frying

Olive oil (blend of refined and virgin) and sunflower oil containing added methanol phenolic extracts of dry rosemary and olive vegetable water or the synthetic antioxidant BHA in combination with the extracts, were used in a frying process. Eight frying operations were performed at 180 °C with 24 hr intervals between fryings. During the frying period the trans fatty acids (TFA) by capillary column gas chromatography (CC-GC) were determined. Trans fatty acids of oleic and linoleic were increased with frying time in both the control oil samples. The rosemary additives (extracts) alone and in combination with BHA decreased the level of trans fatty acids (mainly elaidic acid), while the addition of olive vegetable water did not have any effect.Aceite de oliva (mezcla de virgen y refinado) y aceite de girasol con extractos fenólicos de romero seco y aguas de vegetación de aceituna, o con el antioxidante sintético BHA en combinación con los extractos, se usaron en proceso de fritura. Se realizaron 8 operaciones de fritura a 180°C con intervalos de 24 h. Se determinaron los ácidos grasos trans (TFA) por cromatografía de gases en columna capilar (CC-GC). Los ácidos grasos trans de oleico y linoleico aumentaron con el tiempo de fritura en las muestras de aceite control. Los extractos de romero, solos y en combinación con BHA, disminuyeron los niveles de ácidos grasos trans (principalmente ácido elaídico) mientras que la adicción de aguas de vegetación de aceituna no tuvo ningún efecto.