Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation.
Heating/frying and reuse of edible fats/oils induces chemical changes such as formation of trans fatty acids (TFAs) The aim of this study was to investigate the effect of heating/frying on formation of TFAs in fats/oils. Using gas chromatography with flame ionisation detector, TFA was estimated in six commonly used fat/oils in India (refined soybean oil, groundnut oil, olive oil, rapeseed oil, clarified butter, partially hydrogenated vegetable oil) before and after subjecting them to heating/frying at 180degC and 220degC. All six fats/oils subjected to heating/frying demonstrated an increase in TFAs (p<0.001) saturated fatty acids (p<0.001) and decrease in cis unsaturated fatty acids (p<0.001) The absolute increase in TFA content of edible oils (after subjecting to heating/reheating) ranged between 2.30+ 0.89g/100g and 4.5+ 1.43g/100g; amongst edible fats it ranged between 2.60+ 0.38g/100g and 5.96+ 1.94g/100g. There were no significant differences between the two treatment groups (heating and frying; p=0.892) Considering the undesirable health effects of TFA, appropriate guidelines for heating/re frying of edible fats/oils by Asian Indians should be devised.
Food chemistry