A comparison of volatile compounds in fish sauces prepared from silver carp by use of soy sauce Koji and lactic acid bacteria with those in Chinese commercial fish sauces

Fish sauces were prepared from round silver carp using soy sauce Koji inoculated with Aspergillus oryzae plus lactic acid bacteria Tetrogenococcus halophilus (No. 1), soy sauce Koji (No. 2), lactic acid bacteria (No. 3), and no starter microorganisms (No. 4). These fish sauces were compared in the volatile compounds identified by SPME method and GC/MC analysis among Nampla from Thailand and Fujian fish sauce (FFS) from China. In Nampla, many kinds of volatile acid (VA) including butanoic acid were detected. However. in the fish sauces Nos.1 and 2, no butanoic acid was detected, and there was much of VA in the fish sauce No. I while there was some VA and alcohols in the fish sauce No. 2. In the fish sauces Nos.3 and 4, a few kinds of VA and 1-penten-3-ol were detected while there were many kinds of hydrocarbons in the fish sauce No. 3, and alcohols in the fish sauce No. 4. In FFS, much of VA including butanoic acid and trimethylamine was detected. The result of sensory evaluation indicated that the panelists preferred the flavor of the fish sauces Nos. I and 2 to that of Nampla, while they rather disliked FFS, and the responses to the fish sauces Nos. 3 and 4 were at almost same level as that to Nampla.