Influence of Thermal Processing on the Formation of Trans Fats in Various Edible Oils

Abstract

Trans fats are popular owing to their low cost and potential to increase the shelf life of processed foods but also associated with various risk factors. The present study is focused on the impact of oil processing, like frying, on the formation of trans fats in commercially available edible oils. Scanning electron microscopy was carried out to observe the structural changes in the frying material. The physicochemical analysis of processed edible oils was carried out, while the formation of trans-fatty acid (TFA; elaidic acid) during processing was measured by gas chromatography-flame ionization detector (GC-FID). Furthermore, levels of TFA, i.e., elaidic acid, were found higher in oil samples with potatoes than the oil samples without potatoes. It is proposed that trans fat content could be reduced by using the high-quality frying medium as well as avoiding the repeated frying in order to improve the quality and nutritional value of the diet and avert risk factors. PRACTICAL APPLICATIONSTrans fats are popular owing to its low cost and potential to increase the shelf life of processed products and contribute suitable features to the food. Presently, trans fat intake is considered as a peril factor for cardiac heart diseases, diabetes, cancer and other allied disparities. The present study is focused on the impact of oil processing, like frying, on the formation of trans fats in commercially available edible oils. It aims at quantification of trans fats in oils during frying as well as evaluation of the quality attributes of fried edible oils. Structural changes in the tissues of fried material were also observed through electron microscopy. The results obtained showed that parameters like free fatty acid level, specific gravity, peroxide value, saponification value and iodine value were significantly different depending upon the processing conditions. The formation of TFA (elaidic acid) during processing measured by GC coupled with FID and its higher proportion was observed in the oil samples with potatoes than in the oil samples without potatoes. So it is suggested that trans fat should be minimized in daily diet to improve the quality and nutritional value of edible oils.

Effect of Frying Temperature and duration on the Formation of Trans Fatty Acids in Selected Fats and Oils

“…These factors may change a double bond from a cis position to a trans position (geometric isomerization) or move to another position in the carbon chain (positional isomerization) and both types of isomerization may occur in the same molecule [11]. Different trans isomers can be formed depending on difference factors affecting their production [12].…”