Studies on Salting and Drying Fish. II. Dynamic Aspects of the Salting of Fish

Abstract

SUMMARY— The diffusion coefficient for the penetration of salt into swordfish muscle was not constant but depended upon the salt concentration in the muscle and upon the temperature; the coefficient‐salt concentration curve for 25°C had a minimum value at a salt concentration of approximately 1.5 moles/liter and was always lower in fish muscle than in aqueous salt solutions of the same salt concentration as the muscle. Other parameters which also served to characterize the migration of salt in fish muscle were determined as follows: the equivalent conductance of salted fish muscle was found to be an inverse linear function of the square root of the salt concentration in the muscle and to be always lower in muscle than in aqueous solutions of the same concentration as the muscle; the sodium and chloride ion transference numbers, found to be approximately of the same magnitude in muscle and in water, exhibited the same qualitative variation with salt concentration and with temperature in both media. As in aqueous solution, the diffusion coefficient and the equivalent conductance of salt in fish muscle were found to increase with increasing temperature. It was found that experimental values of the diffusion coefficient at a given temperature agreed reasonably well with values predicted by the equation is the diffusion coefficient in the muscle at infinite dilution and γ is the “mean molar activity coefficient” of salt, also in the muscle, at concentration c. The activation energies for salt diffusion in fish muscle and in water at infinite dilution were both found to be of the order of 4700 calories per gram‐mole, a value within the region of hydrogen‐bonding energies.

Study of sea bass (Dicentrarchus labrax L.) salting process: Kinetic and thermodynamic control

“…D e was then obtained from the fitting equation that appears in the graph, being 1.30 · 10 À10 m 2 /s. Although in a lower range, this value agrees with the literature values for other fish spices (Del Valle & Nickerson, 1967;Peters, 1971;Rodger, Hastings, Cryne, & Bailey, 1984; Table 1 Regression coefficients (b) and partial correlations (R 2 -part) (obtained from stepwise multiple regression) for each independent variable (t: salting time; M 0 : initial weight; Th: thickness; A:…”

“…There are salting processes with kinetic control, with the end of the salting process fixed at a certain time, which is dependent on the salting procedure (pile, brine or kench salting) (Barat, Rodríguez-Barona, Andres, & Fito, 2003), temperature (Del Valle & Nickerson, 1967), pressure (Barat, Grau, Pagán-Moreno, & Fito, 2004) and the raw material characteristics such as freshness (Barat et al, 2006), storage method (Røra & Einen, 2003), feed, size, shape (Zugarramurdi & Lupin, 1980), pH, moisture and fat content (Gallart-Jornet et al, 2007). The main disadvantages of this control principle are the need for high amounts of salting agent and the relatively high variability in water activity, moisture and NaCl content of the final product, which can be critical in case of the lightly salted products stored under refrigeration.…”

Diffusion of sodium chloride in pork tissue

“…In contrast, high values of the diffusion coefficients are reported in literature by Sabadini et al (1998) that obtained a value of the diffusion coefficient of NaCl of 19.37 · 10 À10 m 2 /s dry salted beef at 20°C. Del Valle and Nickerlson (1967) reported values of diffusion coefficients ranging between 11.8 and 14.5 · 10 À10 m 2 /s at 25°C in fresh Swordfish muscle immersed in NaCl concentrations ranged from 5.8 to 180 g/l. These values extremely high are close to the diffusion coefficients of NaCl in pure water (D = 8.16 · 10 À10 m 2 /s at 4°C and 14.8 · 10 À10 m 2 /s at 25°C).…”

Studies on salting and drying of sardine (Sardinella aurita): Experimental kinetics and modeling

“…Length of salting period as well as salt concentration depends on the expected final product. Barat, Rodriguez-Barona, Andrès, and Fito (2002) show that salted fish weight is related to brine concentration, meanwhile temperature effect during salt diffusion into a food product is low (Del Valle & Nickerson, 1967). Traditionally, sun drying is widely used for drying fish.…”