A comparison of two frying oils, cottonseed oil and corn oil, using standard methodologies and modified methodologies

The fry life of winterized nonhydrogenated cottonseed oil (CS) and nonhydrogenated corn oil (CO) were compared in 70 frying hours using standard objective analysis and a modified approach for volatile olfactory analysis of fried oils. Objective evaluations such as free fatty acid, iodine value, p-anisidine value, and Hunter color lab indicated significant differences between CS and CO especially between 20 and 30 fry hours. p-Anisidine value rose sharply the first 10 hours in both CS and CO then continued to rise and plateau. Free fatty acid and Hunter color (L*a*) increased with frying time and iodine value and hunter color (b*) decreased with frying time in both CS and CO. Gas Chromatography/Mass Spectrometry/Olfactory (MS/GC/O) evaluations indicated more volatiles present at 10 and 70 frying hours than at 0 fry hours, in both CS and CO. The methods and parameters used in this research indicated that deterioration in oil quality occurred for CS and CO, significant differences between CS and CO were present, and the modified methods used allowed for further observations in the monitoring of oil quality.