Microbial reclamation of fish processing wastes for the production of fish sauce

In order to enhance the economical values of bonito and reduce the environmental problems caused by the wastes from bonito processing, the possibility of utilizing fish wastes for fish sauce production was investigated. Fish sauces were prepared experimentally from bonito wastes with or without the addition of various enzymes including viscera itself, soybean koji, and ang-khak. Preparations with the whole fish were also carried out for comparison. Fish sauce products with similar quality were obtained when the wastes and the whole fish were used as the raw materials. Fish sauce with better sensory flavor was obtained from the ang-khak treatment. Volatile compounds of fish sauce samples were separated, identified by Gas Chromatography-Mass Spectroscopy. A total of 23 volatile compounds were identified, which may contribute to the aroma of the fish sauces. These aroma compounds of the fish sauces were mainly from lipids, amino compounds, and sugars of the raw materials, in which lipid was the major contributor.