AbstractA comparative study of cottonseed and peanut oils for frying of potato chips was undertaken. Industrial scale frying was conducted for 5 days with cottonseed and 5 days with peanut oil and frying oils and chips were sampled twice a day. Frying oils and oils extracted from stored chips were analyzed for ultraviolet absorption (A232 and A268), peroxide and acid values. Tocopherol and tertiary butylhydroquinone levels were determined by high performance liquid chromatography. Chips stored at room temperature for 12 weeks were organoleptically evaluated. During the first 20 hr frying the A232, free acid and peroxide values of cottonseed oil increased rapidly, exceeding that of peanut oil, which increased moderately. For both oils, constant values were attained during the next 80 hr period, followed by moderate increases during the last 23 hr. Peanut frying oil lost 55% of its tocopherols and 54% of its tertiary butylhydroquinone during frying (103 hr), whereas cottonseed frying oil retained these compounds at the original levels. Tocopherols were also better retained in chips fried in cottonseed oil than in peanut oil. The fatty acid patterns of frying oils and oils extracted from chips did not show significant changes due to frying and storage, respectively. These results, therefore, suggest that cottonseed oil is sufficiently stable to be used as a substitute for peanut oil in deep frying.