A study of the applicability of a modified thiobarbituric acid test to flavor evaluation of fats and oils

A modified thiobarbituric acid test has been devised for the determination of certain components of oxidized fat. The reaction was carried out in a single phase solvent designed to eliminate the color extraction or fat removal steps of other TBA tests. A moderate temperature of 60C, with no added acid, was used to minimize breakdown of hydroperoxides and TBA. Under certain reaction conditions, temperature, sunlight, ferric ion, and oxygen can influence results. Of the aldehydes examined, the TBA reaction products of dienals showed an absorption peak at 532 m dm only, while the TBA reaction products of the saturated aldehydes showed a peak at 452 mॖ only. The spectral behavior of TBA reaction products of monoenals was found to vary with the location of the double bond. Fat samples, aged at either 60C or 37.8C, were examined organoleptically and by the modified TBA test. The 452 mॖ peak was of value in assessing the flavor of beef fat, cottonseed oil, and used frying fat, whereas the 532 mॖ wavelength was of value in assessing the flavor of soybean oil, used frying fat, and pork fat.