Influence of Salting Technology on the Diffusion of NaCl in Swordfish (Xiphias gladius) Fillets

Swordfish is the most widespread billfish in the aquatic environment. The industrial processing of swordfish fillets involves salting, drying, and smoking steps. Salting techniques, dry or wet, are the most common method of fish preservation. This work evaluated salt diffusion in swordfish fillets after traditional dry salting and wet industrial injection salting methods. The data obtained from the dry salting studies highlighted that the salt diffusion process in swordfish meat was an unfavorable process depending on the contact time with the salt/meat. Moreover, irregularly shaped fillets negatively affected the salt migration in the different areas, leading to inhomogeneous and possibly unsafe final products. On the contrary, wet injection salting was suitable for processing swordfish fillets. As a result, the final products had a homogeneous salt concentration, maintained the organoleptic characteristics and health benefits for a long period, and achieved a longer shelf-life. Furthermore, the water activity (aw) values detected for the different processed fillets confirmed the physicochemical features of the final products and allow the classification of safe products. Moreover, injection salting is a quick process compatible with industrial production times.