Volatile compounds of Baltic herring analysed by dynamic headspace sampling-gas chromatography-mass spectrometry

The effect of storage time at 6 degreesC on the volatile compounds of Baltic herring was studied using the dynamic headspace-gas chromatography-mass spectrometry method. The fish were baked just before analysis. In the headspace of baked, fresh herring (I day storage) the most abundant volatiles were 3-methylbutanal, 2-methylbutanal and hexanal comprising 18, 16 and 13% of all volatiles, respectively. When the fish were stored for 3 days the proportions of 4-heptenal, 2-heptanone and octatriene increased significantly. After further storage the peak areas of hexanal, heptanal, 1-penten-3-ol and octadienes also increased many-fold, which indicated the oxidation of long chain unsaturated fatty acids. After 8 days storage several volatile compounds were detected in the baked fish which were not found in freshly baked herring. Some compounds related to microbial spoilage (3-methyl-1-butanol, cresol) were identified.