Photon correlation spectroscopy in the fish salting process

Abstract

The current study experimentally investigates the innovative photon correlation spectroscopy method application in fish salting process. The method is based on the Rayleigh scattering of light by a substance. The experiment aims to study the mass transfer laws, as well as technological and practical aspects of the fish salting process in brine without circulation. The paper focused on spatio-temporal dependence of the salt diffusion coefficients in the fish-brine system and their correlation with temperature, indicating that at a temperature close to 8°C a diffusion-osmosis equilibrium occurs between the brine and the muscle tissue of fish. The salt diffusion rate was estimated, confirming the validity of the Crean’s frontal theory of salt mass transfer in muscle tissue of fish. Based on the Stokes-Einstein equation, it was shown that the dynamic viscosity of fish tissue fluid could be determined by changing the diffusion coefficient and the diffusing particles size. Practical applications Fish salting is an important preservation method in many countries. The present work seeks to investigate the salting of herring, as it is prone to ripening during this process. Excessive sodium chloride consumption is known to have a negative effect on humans. At the same time, the salt content in the product is interrelated with its preservation effect. In this regard, it is necessary to accurately calculate the specified salt concentration in the finished product for the optimal shelf life. Improvement of this process requires a better understanding of the mass-transfer mechanisms using modern investigation methods. Research focuses on spatio-temporal salt distribution in fish muscle tissue to arrive at clear conclusions, which can facilitate the improved production of salted fish and can be widely used in the food industry for processing and preserving fish or fish products.