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Electrodialysis Desalination of Fish Sauce: Electrodialysis Performance and Product Quality



ABSTRACT:  Fish sauce has a unique, pleasant flavor, but contains high levels of sodium chloride, which is nowadays not desirable for health-conscious consumers. Although many researchers have attempted to solve this problem by substituting sodium with potassium in fish sauce, potassium-based products are still unsuitable for patients with kidney disease. Thus, electrodialysis (ED) desalination of fish sauce was carried out. The rate of salt removal, evolution of total soluble solids, and electrical conductivity of the electrodialysis-treated fish sauce were investigated. Moreover, the system performance in terms of yield, energy consumption, and current efficiency were examined. Density, viscosity, ion concentrations (that is, Na+, K+), total nitrogen, amino nitrogen, and color were investigated at various values of input voltage (6, 7, and 8 V) and remaining salt concentration (22%, 18%, 14%, 10%, 6%, and 2%[w/w]). The results indicated that an increase in the input voltage led to an increase in the rates of salt removal, electrical conductivity, and total soluble solids. The energy consumption increased whereas current efficiency and yield decreased significantly with an increase in input voltage and the salt removal level. Physicochemical properties of the treated fish sauce, in terms of the total soluble solids, density, viscosity, ion concentrations (that is, Na+, K+), total nitrogen, and color were significantly affected by the input voltage and the salt-removal level.