Abstract:

Pomfret and grass carp were chosen as representatives of sea and freshwater fish, respectively to investigate
odor changes by electronic nose (E-nose) and changes in volatile flavor components during chilled storage by gas
chromatography-mass spectrometry (GC-MS). The results showed that e-nose could distinguish the odor of different
species of fish at different storage periods, and the odor changes of grass carp were much more obvious. A total of 22 and
19 volatiles were identified in pomfret and grass carp, respectively, during refrigeration, mainly consisting of aldehydes,
alcohols, esters, and putrefactive compounds etc. The major volatiles of fresh pomfret were 1-penten-3-ol, 1-octen-3-ol,
hexanal, heptanal and 2-octenal, while the major volatile of grass carp was caproic acid methyl ester. There were different
changes in odorous components of pomfret and grass carp during refrigeration. The putrefactive compounds of pomfret
were mainly trimethylamine and 3-methyl-butanol, and the contents of most aldehydes and alcohols showed a decreasing
tendency. The fat oxidation products decanal, 1-octen-3-ol, hexanal and nonanal were found to be the main volatiles of grass
carp stored for two and four days. Moreover, fewer putrefactive compounds were detected during the late storage period.
The above results noted that growing environment, lipid oxidation and microbial spoilage may influence the odor of sea fish
and freshwater fish during cold storage.

Key words: pomfret, grass carp, electronic nose, gas chromatography-mass spectrometry (GC-MS), volatile compounds