Modelling water and salt diffusion of cold-smoked Atlantic salmon initially immersed in refrigerated seawater versus on ice

The effect of dry salting during the cold-smoking process was evaluated on Atlantic salmon initially stored in refrigerated seawater (RSW) or ice. A 2D mathematical model was developed from first principles, simulating the heat and mass transfer process during dry salting at increasing salting duration. This model was validated using experimental values and compared with the empirical model of Zugarramurdi and Lupín. The predicted values were used for water activity prediction and validated. It was found that salting duration influenced drip loss, redness and yellowness, texture, water activity, salt uptake and water loss. Smoked salmon from RSW fish were more reddish with a lower water activity than iced fish after vacuum storage. Drip loss and colour were significantly influenced by the processing step (salting, smoking and storage). Overall, the model presented reasonable predictions for temperature, salt and water content, water activity and was in close agreement with the empirical model.