Mass transfer processes modeling in the production of dried and air-dried fish

Abstract

The focus areas for the Fisheries industry in Russia are increasing the share of products with high added value and development of the domestic consumer market of fishery products. In the Russian Federation the products made of aquatic bioresources, such as stock fish, air-dried and dried fish, are traditionally in strong demand with the population. It has been determined, that the manufacture of these fish products remains at a low level. In order to increase the volume of dried and stock fish production, improve the product’s quality specifications, it is necessary to develop the technology of the drying process, as well as to find the ways and methods to decrease the drying time. The efficiency of these productions can be increased by using the scientific-based process solutions that allow to keep the production costs down, improve the consumer properties of the end products and ensure its safety. The generalized dependences for calculating the duration of dehydration in production of air-dried and stock fish products have been developed in this study. The generalization has been performed based on the ratio of the current moisture content of fish to the first and second critical moistures of the kinetics curves of dehydration. A formula for calculating the current moisture content depending on the duration of the dehydration process and the dependence for calculating the drying time in relation to fish moisture have been introduced. The patterns received allow to model the kinetics curves of fish dehydration. A functional relation between the critical moistures of the kinetics of dehydration, the water diffusion coefficients and the initial moisture content has been determined. The derived dependencies allow to calculate the diffusion coefficients in the critical points of the kinetics curve of dehydration. The obtained formulas could be used for calculating the water diffusion coefficients in fish. Using the suggested formulas makes it possible to solve the diffuse type partial differential equation. This gives an opportunity to model the water distribution in fish during the process of dehydration.