Effects of β-carotene on the thermal oxidation of fatty acids

Abstract

β-Carotene is one of the most important fat soluble pigment with well known antioxidant and provitamin A activities. It is used in industries as food colorant and a source of vitamin A. The thermal induced degradation during processing leads to color and properties losses. The thermal stability of the fatty acids composition of edible oils is of great importance to food manufacturers. Corn oil, rapeseed and sunflower oils were fortified with 50 to 300 μg/g of β-carotene and oxidized using Rancimat (air flow rate 20 L/h) at 110°C for 14 h. Fatty acid methyl esters (FAMEs) were measured using gas chromatography with Agilent-Technologies DB-Wax capillary column. It was found that by adding β-carotene (50 to 300 μg/g) to the corn, rapeseed and sunflower oils, no significant changes was observed in saturated fatty acids. Saturated fatty acids were relatively more protected in the presence of unsaturated fatty acids of similar carbon atoms and in the presence of β-carotene. The addition of β-carotene affected the composition of unsaturated fatty acids in the tested oils. Thus, β-carotene acts as a pro-oxidant in highly unsaturated sunflower oil. Unsaturated fatty acids are oxidized earlier and results to the formation of unpleasant flavor and consequent rancidity. Key words: β-Carotene, lipids oxidation, thermal stability, edible oils, fatty acids composition.