Analysis of volatile compounds as spoilage indicators in fresh king salmon (Oncorhynchus tshawytscha) during storage using SPME-GC-MS

A method was developed for the analysis of salmon volatiles using solid-phase microextraction and gas chromatography-mass spectrometry. This method was used to monitor the volatiles of fresh king salmon ( Oncorhynchus tshawytscha) stored in ambient air or in a 40: 60 ( v/v) mixture of CO2: N-2 over time. The levels of several of the volatile compounds were found to change during storage, with some showing a clear difference between storage in air and storage in CO2: N2. Of these, several alcohols ( cyclopentanol, Z-2-penten-1-ol, 1-penten-3-ol, and 1-octen-3-ol) and aldehydes ( hexanal, octanal, E-2-pentenal, and E-2-hexenal) were identified as potential markers for salmon freshness. Several other volatiles ( acetoin, ethyl benzene, propyl benzene, styrene, 3-methyl butanoic acid, and acetic acid) were identified as potential markers for salmon spoilage. A comparison of salmon harvested with and without the "rested harvesting" technique showed that E- and Z-isoeugenol levels were increased by the use of the isoeugenol based anesthetic. The use of the anesthetic did not affect the levels of any of the other compounds identified.