Estimating carbonyl compounds in rancid fats and foods

Abstract

Summary A convenient method for the quantitative determination of the carbonyl compounds in fats and oils is described. The procedure is based upon the formation of the 2,4‐dinitrophenyl hydrazones of the carbonyl compounds in the presence of trichloroacetic acid catalyst and the colorimetric determination of the hydrazone compounds in alkaline solution. Standardizations are presented for the simultaneous determination of saturated and allenic carbonyl content from the absorbences at 430 and 460 mµ. Applications of these procedures to edible oils are described, and data are presented showing the carbonyl values in relation to other criteria of change. The problem of correlating changes in the carbonyl content of oils with flavor deterioration is now under investigation.