Influence of Different Salt Concentrations and Addition of Commercial Enzyme on the Chemical Characteristics of Fish Sauce from Round Scad (Decapterus maruadsi)

The effects of salt concentrations and addition of Flavourzyme on the chemical characteristics of fish sauce were studied. The fermentation mixtures were prepared by mixing fish with salt at one of two levels (25% or 30%) and Flavourzyme supplementation at 0%, 0.1%, 0.3%, and 0.5% based on fish weight, and fermented at the ambient temperature ranging from 25 to 32 °C for three months. The results showed that the fish sauces with 25% salt contained total nitrogen of 17.4 - 25.3 g/L, amino acid nitrogen of 8.1 - 13.5 g/L, and ammonia nitrogen of 1.2 - 1.9 g/L. For fish sauces with 30% salt, these contents were 16.3 - 24.2 g/L, 7.2 - 12.2 g/L and 1.1 - 1.5 g/L, respectively. The fish sauces with 25% salt had amino acid nitrogen contents of 8.1 g/L for sample without Flavourzyme and 10.9 - 13.5 g/L for samples with Flavourzyme. The higher enzyme levels gave higher yield, total nitrogen, and amino acid nitrogen contents but lower ammonia nitrogen and pH values. This study suggested that the fish sauce produced using 25% salt and 0.3% Flavourzyme was appropriate. Flavourzyme could be a potential enzyme applied to improve the chemical properties of fish sauce.