Study of sea bass (Dicentrarchus labrax L.) salting process: Kinetic and thermodynamic control A. Fuentes, J.M. Barat * , I. Ferna ´ndez-Segovia, J.A. Serra Departamento de Tecnologı ´a de Alimentos, Universidad Polite ´cnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain Received 26 September 2006; received in revised form 19 July 2007; accepted 24 July 2007 Abstract The development of salted products from sea bass could contribute to diversify its current offer. Establishing the most appropriate salting method would be the first step towards obtaining high quality salted products. The aim of this work was the study of kinetic and thermodynamic control of sea bass salting process. First of all, the kinetics of the salting process was studied, by analyzing the influ- ence of the process variables (moisture content, water activity, sodium chloride and total weight change) at different salting times, in order to obtain the time required to achieve a fixed salt content. In the case of thermodynamic control, the objective was to determine the amount of salt to be added to reach a previously fixed salt concentration. The obtained results point to some advantages of the ther- modynamic control method over the kinetic method; in that it offers higher homogenization of the salted fish and a more easy to control salting procedure. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Sea bass; Salting; Mass transfer 1. Introduction Salting is one of the oldest techniques for fish preserva- tion, and is essentially intended to increase the shelf life of the product depressing water activity by means of dehydra- tion and salt uptake by the fish muscle. However, the cur- rent demand for salted fish is driven more by the flavour of the product than for preservation purposes (Mujaffar & Sankat, 2005). In Mediterranean countries, the most common species used as salted fish are cod, tuna, anchovy and sardine. However, in the Mediterranean Sea, aquaculture is focused on other fish species such as sea bass (Dicentrachus labrax) and sea bream (Sparus aurata) which, in these countries, account for 90% of world production. Traditionally, sea bass has been used almost exclusively for fresh consump- tion, but the high current volume of production and low prices mean that sea bass can be industrialized to obtain other processed products. As regards the salt content in commercial salted and smoked fishes, high variability has been reported by differ- ent authors (Espe, Kiessling, Lunestad, Torrissen, & Røra, 2004), which may have implications for food safety and lead to products with different salty taste. For this reason, it would be interesting to establish controlled salting proce- dures to provide consumers with homogeneous products and, consequently, a reproducible salty taste. Fish salting is generally accepted as a diffusive process. According to Fick’s law, water and salt diffusion is con- trolled by the moisture and sodium chloride gradients and by the water and salt diffusivity coefficient (D e ). D e val- ues depend on fish characteristics, including temperature, freshness, pH, structure and composition as well as piece dimensions. The salting process that could be used for obtaining salted fish products can be classified according to the con- trol mechanism: kinetic and thermodynamic. There are salting processes with kinetic control, with the end of the 0956-7135/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2007.07.014 * Corresponding author. Tel.: +34 96 387 73 65; fax: +34 96 387 73 69. E-mail address: jmbarat@tal.upv.es (J.M. Barat). www.elsevier.com/locate/foodcont Available online at www.sciencedirect.com Food Control 19 (2008) 757–763