The behavior of the diffusion coefficients in salting of herring in a fixed brine at subzero temperatures

The relevance of herring brine salting at subzero temperatures, taking into account the positive dynamics of its catching, its reserves, a favorable cooling effect on the suppression of microorganizms activity, improvement of product quality and increasing of storage time are indicated in this paper. Changes in such a significant characteristics as the diffusion coefficient in the process of salting at subzero temperatures were studied. Method of photon correlation spectroscopy, based on the Rayleigh scattering of radiation from the substance was used for the study. The experimental diffusion coefficient dependences on the depth of penetration of the salt in brine, skin and meat of herring at temperatures ranging from -16 ° C to -6 ° C were obtained. They are of wave-like nature. The dependence of the diffusion coefficients on subzero temperature ranging from -18 ° C to 0 ° C, and having a harmonic form was also obtained in the work. The resulting temperature gradient is a source of perturbations, giving rise to thermoconvective waves. According to the theoretical research of Academician A.V. Lykov and chemical processes occurring at the border (skin) of phase separation using the basic equation of thermochemistry - Gibbs law, mechanism of thermoconvective waves influencing the diffusion coefficient is explained. A relation between the diffusion coefficients with the size of the diffusing particles, having hyperbolic character in the temperature range from -18 ° C to 0 ° C in the in brine, skin and meat of herring was determined. The possibility of acceleration of salting by means of mechanical impact on the object under study (in particular sound or ultrasound) was expressed. The destruction of the diffusing particles, representing the union of Na+ and Cl- with water molecules, increases the diffusion coefficient.