Effect of processing parameters on water activity and shelf life of osmotically dehydrated fish filets

• Gilthead seabream fillets were osmotically treated and stored under refrigeration.
• Osmotic treatment extended significantly the shelf life of chilled fish fillets.
• Pseudomonas dominated spoilage of untreated and osmotically treated fish fillets.
• An Arrhenius-type model described the effect of processing on Pseudomonas growth.
• Model can be used as a tool for predicting shelf life of osmotically treated fish fillets.

The objectives of the study were to evaluate the effects of osmotic solution concentration on the mass transfer kinetics during osmotic dehydration and to develop a predictive model for the effect of storage temperature and aw on the shelf life of osmotically dehydrated gilthead seabream fillets. A first degree polynomial model was chosen for the description of aw as a function of maltodextrin concentration in the osmotic solution and processing time. A mathematical model was developed, based on a modified Arrhenius-type equation, for predicting the combined effect of temperature and aw on the growth rate of Pseudomonas spp. in fish during refrigerated storage.