Oxidative Stability of Frying Oil and Kinetics of Unsaturated Fatty Acids Oxidation under the Frying Condition of Western-style Fast Food Restaurants

This study investigated the oxidation stability of five common frying oils during frying under western fast food conditions. Their oxidation kinetics of unsaturated fatty acids (linolenic acid, linoleic acid, and oleic acid) were analyzed. The results showed that palm oil exhibited the best oxidation stability during frying based on its significantly lower increase rates in anisidine value and total oxidation value, and lesser decrease rate in iodine value among all the frying oils tested. The oxidation kinetics of linolenic acid in soybean oil and rapeseed oil, and linoleic acid in palm oil, rapeseed oil, sunflower oil and rice bran oil agreed with the zero-order and first-order reaction kinetics models. However, the linoleic acid in soybean oil only followed the first-order reaction kinetic model. Besides, the changes of oleic acid in palm oil, soybean oil, rapeseed oil and sunflower oil during the reaction were consistent with the zero-order and first-order reaction kinetics models. The coefficients of determination of models were between 0.886 and 0.987, above 0.85, showing an excellent fitting degree of models. It was indicated that these oxidation kinetic models of unsaturated fatty acids in frying oils were feasible.