Effects of Mixing Canola and Palm Oils with Sunflower Oil on the Formation of Trans Fatty Acids during Frying

GLC analysis was conducted to indicate the formation of trans- C18 fatty acids of sunflower, canola and palm oils during frying. Blends of sunflower oil and palm oil or canola oil were obtained by mixing sunflower oil with palm or canola oils at the volume ratios of 60: 40, 40: 60 and 20: 80 (v/v), then heated at 180?C ± 5?C for 5, 10, 15 and 20 h in the atmospheric oxygen. GLC results demonstrate that the formation of trans C18-fatty acids was generally dependent upon the frying time and oil mixing ratios. Furthermore, mixing sunflower oil with oils rich in monounsaturated fatty acids (palm or canola oils) lowered the formation of trans-C18 fatty acids during frying.