Salting is one of the main processes of preservation in meat and fish industry. Knowledge of how salt affects the muscle microstructure is needed both to model diffusion and to obtain the desired salt concentration in the product. Diffusion of sodium chloride was studied in a gelled minced fish ball-brine system. Systems with both closed circulation of the brine and static conditions were used to study and compare the salt transport process. Effective diffusion coefficients (De) for diffusion of sodium chloride into fish. balls made from fresh and frozen haddock mince were determined. A numerical calibration of an analytical model based on Fick's second law was performed, in which salt diffusion follows a non-steady-state process. Critical experimental parameters for the estimation of diffusion coefficients were: size of balls, initial solute concentration in the bulk of brine, freezing of the material before the treatment, and stirring of the brine. The result of experiment shows that a simple fish ball brine system can be used to model mixing of salt in brining processes. (C) 2015 Published by Elsevier Ltd.