Volatile Carbonyl Compounds from Heated Beef Fat

Abstract

Volatile carbonyl compounds produced in beef fat heated at 150°C in nitrogen were investigated. Ethanal, propanal, isobutanal, isopentanal, crotonal, benzaldehyde, acetone, methyl ethyl ketone, methyl isobutyl ketone, glyoxal, and pyruvaldehyde were isolated as their 2, 4-dinitrophenylhydrazones and identified by means of thin layer chromatography, infrared, mass and proton magnetic resonance spectroscopy. These carbonyls were considered to be contained also in the volatiles from beef fat heated in air from the results of thin layer chromatography.
Volatile carbonyl compounds of longer carbon chain produced in beef fat heated at 200°C in air were also examined, and hexanal, heptanal, 2-heptenal, octanal, 2-octenal, nonanal, 2-nonenal, 2-decenal, 2, 4-decadienal and 2-undecenal were tentatively identified by gas-liquid chromatography. The amount of long-chain carbonyls was larger and the oily odor in beef aroma was stronger in beef fat heated in air than in nitrogen.