Removal of salt and organic acids from solution used to season salted Japanese apricots (ume) by electrodialysis, precipitation and adsorption.

With the aim of repeatedly reusing the solution used to season salted ume (Japanese apricot), we investigated its desalting and deacidification by electrodialysis, precipitation, and adsorption. Although NaCl and acids could be easily removed from used seasoning solution by electrodialysis, useful substances such as amino acids were removed at the same time. Precipitation using Ca(OH)2 could remove only organic acids, but the treated solution became bitter. Two weakly basic commercial resins, DIAION WA30 and Chitopearl CCS, adsorbed organic acids selectively. Chitopearl CCS in particular selectively adsorbed citric acid in the used seasoning solution without also adsorbing useful substances. The equilibrium data of a citric acid, which was a main organic acid, were correlated by the Langmuir equation. The saturation capacity decreased with increasing concentrations of NaCl in the solution but the equilibrium constant did not change. By combining electrodialysis and adsorption, NaCl and organic acids could be removed while amino acids largely remained. The resultant solution was considered to be suitable for repeated reuse.