Chemical reactions involved in the deep fat frying of foods. II. Identification of acidic volatile decomposition products of corn oil

Chemical identification of the volatile decomposition products (VDP) produced by fats and oils under conditions of deep fat frying is important for the elucidation of the mechanisms of thermal oxidation, for the study of their effects upon human nutrition, and for their contribution to the deep fat fried flavor of foods. The acidic VDP produced by corn oil maintained at 185C for 30 hr with periodic frying of moist cotton balls and with addition of fresh oil to replenish the oil lost due to evaporation, decomposition, and adsorption by the cotton balls were fractionated by repeated gas chromatography. The gas chromatographic fractions were identified by IR and mass spectrometry. A total of 30 acids were characterized. They consisted of 12 n‐aliphatic saturated acids, seven 2‐enoic acids, one 3‐enoic acid, three keto acids, two hydroxy acids, four dicarboxylic acid and one aromatic acid. It is suggested that the effects of some of these acids upon human nutrition be studied.