Application of the SAFES (systematic approach of food engineering systems) methodology to salting, drying and desalting of cod

SAFES methodology was applied to cod process where three matrix of changes were defined corresponding to the three main stages of the process. Due to insufficient experimental data to completely build the matrix, some related hypotheses were necessary.Specifically, this process consisted of: osmotic dehydration in saturated brine, followed by a drying at 15 °C and desalting by immersion in tap water of cod fillets. During all of which, mass transfer (basically salt, water and protein) occurs by diffusion. A migration of water from extra-intracellular liquid to solid matrix and to external fluid took place in the salting and drying stages. On the other hand, an intake of salt occurred during the process and an amount of it precipitated. However, it was observed that there was a tendency for the opposite to occur in the desalting operation.Moreover, important changes related to protein component were taken into account. During salting, some proteins from raw cod (60%) were denatured (made soluble) due to the high ionic forces in the media. Soluble proteins above mentioned suffered a further precipitation during the drying process and a re-solubilization.