| Changes of physicochemical indexes of soybean oil, rapeseed oil, palm olein, cottonseed oil and frying oil during potato chips frying were analyzed to reflect the quality changes of five kinds of refined oils during frying. The results showed that color could be used as a visual indicator to reflect the level of frying. Acid value could not be used as a good index to evaluate the quality changes of frying oils due to its lag and variability. Peroxide value did not fully reflect the level of frying and could only be used as a reference index. Carbonyl value had a positive correlation with frying time and could be used as a sensitive indicator to reflect the degree of oil deterioration during frying. Oxidative stability indexes of refined oils decreased immediately after frying，and the correlation between oxidative stability index and the degree of frying was poor, which could not be used as a reliable indicator to reflect the frying quality of oils. The polar component was a reliable indicator to evaluate the level of thermal deterioration during oil frying. Overall，the palm olein had the best frying stability comparing with other four kinds of edible oils. |
