The effect of reduced salt content and addition of halophilic lactic acid bacteria on quality and composition of fish sauce made from sprat

Abstract

Six fish sauce samples, three of each containing about 23 and 20% (w/w) salt, were made from sprat (Sprattus sprattus) caught in the North Sea. The effects of different salt concentrations and addition of a halophilic lactic acid bacteria (Tetragenococcus halophilus) on autolysis, chemical composition and organoleptic quality were studied. Both autolytic and microbial activity were highest at the lowest salt concentration, and the low salt samples also had the highest weight per weight protein/salt-ratio (0.5). Apparently, some lactic acid production occured in the low salt sample where both T. halophilus and 1% glucose were added, but it is uncertain whether this acid production contributed significantly to the preservation. Organoleptic evaluation of the sauce samples after 9 months storage showed that several fish sauce samples had an acceptable quality, but all the experimental samples were rated as significantly inferior to first grade commercial Thai fish sauce (Nam pla). To improve tissue solubilization and flavor development, it may be necessary to add some hydrolytic enzymes and a mixture of halophilic bacteria isolated from good quality fish sauce.