Comparison of conventional and countercurrent fresh water consumption in the leaching stage in a surimi manufacturing plant

MARÍA AGUSTINA REINHEIMER; MÓNICA BONFIGLI; NICOLÁS J. SCENNA

Concordia

Congreso; Food Innova 2014. International Conference on Food Innovation; 2014

Universidad Nacional de Entre Ríos (UNER) (Argentina)- Universidad Politécnica de Valencia (UPV) (España) - Instituto Universitario de Ingeniería de Alimentos para el Desarrollo (España)

Surimi is a concentrate of the myofibrillar proteins, primarily myosin and actin of fish muscle, which is mechanically deboned, minced and subsequently the comminuted fish meat is washed in aqueous solutions. One critical unit operation is the water leaching (extraction) step. The objective of this process stage is to remove soluble compounds resulting in concentrated myofibrillar proteins, which mainly contribute to gel formation. The conventional leaching process entails copious amounts of potable water in a lateral flow direction with minced fish, which is disadvantageous from two points of view: operating cost and amount of wastewater discharged. On the other hand, it is well known in different processes that the countercurrent configuration requires less amount of water. This work presents a comparison of washing water requirements for the conventional and countercurrent arrangement in the leaching stage of a surimi manufacturing plant. The leaching process is performed by three continuous cycles of washing, each with a separate set of leaching tank and rotary sieve. A mathematical model to describe the leaching process was formulated and implemented into the optimization environment General Algebraic Modeling System (GAMS). Each cycle in the washing stage is modeled as solid-liquid extraction of sarcoplasmic proteins within fish meat spheres of known diameter, coming from the mincing process stage. Soluble proteins are transferred from the solid matrix of each sphere to the bulk phase of the washing solution. The following phenomenological steps are considered for the mass transfer mechanism during the extraction: entrance of the solvent into the solid matrix, solvent penetration and diffusion inside the solid matrix, solubilization of the soluble compound, transport of the solute to the exterior of the solid matrix by diffusion, and migration of the extracted solute from the external surface of the solid into the bulk solution. Simulation results show that less than 50% of the fresh water requirement is necessary for the countercurrent arrangement and the same quality of product. Thus, countercurrent leaching can reduce water use and therefore it?s operating costs.