Fish Products and Byproducts Technology

Unit 3- Salting and Drying

3.1.2. Theory of salting
How salting takes place (Theory of salting)?
During salting osmotic transfer of water out of the fish and salt into the fish takes places, which effect fish preservation. It is based on different factors like diffusion and biochemical changes in various constituents of the fish. Movement of salt molecules from the brine into the fish takes place through a layer of salt solution covering the fish but having a salt concentration below that of the brine. This layer is formed because the water diffuses out at a faster rate during the initial stages from the fish than the salt solutes, which enters the fish. As the period proceeds the thickness of this covering layer diminishes as its salt content grows. At this point, diffusion of water from the fish ceases and the salt concentration in the layer equals to that of the salt concentration in the in the brine solution. Penetration ends when the salt concentration of the fish equals that of the surrounding medium.