Soy sauce desalting by electrodialysis

Abstract

In this work, microfiltered samples of a traditional soy sauce containing 15.1±0.3% (w/v) of sodium chloride were desalted using a laboratory-scale electrodialyser equipped with a stack composed of nine cation- and eight anion-exchange membranes so as to minimise the health risks associated with the consumption of high-salt foods, as well as to allow its full freezing at the current industrial freezing temperatures and accurate dosage in the formulation of multi-component ready-to-serve frozen meals.Whatever the electric current applied in the range of 2.5–6.5A, the recovery of total acids and amino nitrogen in desalted soy sauce was (80±4)% and (70±3)%, respectively. Moreover, the final concentrations of chloride ions and total solids or electric conductivity were (14±2)%, (73±6)%, or (25±1)% of the corresponding initial ones, respectively. A series of sensory tests proved that the ED-desalted soy sauce kept a good soy sauce aroma without salty aftertaste and its taste did not differ significantly from that of raw soy sauce.