Effect of carrot powder added to dough on oxidation of oil and fried product during frying

초록

Effect of freeze-dried carrot powder added to dough on the thermooxidative stability of frying oil and fried product were studied by determining peroxide (POV), acid (AV) and p-anisidine(PAV) values, contents of polar compound and conjugated dienes, and fatty acid composition. Frying of samples made by sheeting flour dough and cutting to a shape of small square (2 cm x 2 cm) was performed in soybean oil at 160°C for 1 min and repeated every 20 min for 20 h. Addition of carrot powder to dough at 10, 20 and 30% resulted in significantly (p<0.05) higher POV, AV, PAV and conjugated dienes and polar compound formation both in frying oil and in fats of fried products. The least difference in oxidation from oils to have fried ones with carrot powder during frying was found in oils to have fried ones with carrot powder at 20%. This indicates that carrot powder can accelerate formation of peroxides and polar compounds such as aldehydes and ketones mainly due to higher oxidation of the oil. Increased hydrolysis of frying oil, mostly in forms of triacylglycerols, to produce more free fatty acids could be resulted from higher water content in samples with carrot powder. Also higher lipid oxidation observed in fried products is closely related with transfer of the frying oil to the products. The findings suggest that the addition of carrot powder to dough exert an adverse effect on the oxidation of oil during frying.