Abstract: Changes in physical and chemical indexes of frying oil and their correlations were analyzed during potato chips frying in this study. The results showed that the refractive index, color, acid value, carbonyl value and total polar material of frying oil increased with prolonged frying time, peroxide value first increased and then decreased, iodine value displayed a decrease, and changes in specific gravity, viscosity and saponification value were irregular. There were very significant positive correlations among acid value, carbonyl value, total polar material, color and refractive index, and all the correlation coefficients were greater than 0.9. Moreover, total polar material of frying oil could be predicted by acid value and color.

Key words: frying oil, potato chips, quality change