Effect of Sodium Chloride on Meat Tissue Microstructure and its Influence on the Diffusion of Nitrite and Nitrate Salts

PINOTTI, A; CALIFANO, A; ZARITZKY, N

Puebla, México

Congreso; Eigth International Congress on Engineering and Food; 2000

Smoking, salting, and the addition of certain additives (curing salts) are diffusion applications that play important roles in meat processing. The objective of the present work was to analyze the effect of sodium chloride concentration on the diffusion coefficients of curing salts (NaNO2, KNO3) in pork tissue using transient techniques. Cylinders of meat were immersed in solutions of these preservatives; experiments were performed at 4 and 20oC using brine compositions ranging between the concentrations commonly used by the industry. The average concentrations of nitrite, nitrate as a function of immersion time were experimentally determined using spectrophotometric techniques. The unsteady state mathematical formulation was applied considering radial mass transfer in long cylinders of meat tissue. The diffusion coefficients of the salts were obtained fitting the theoretical curves to experimental data. A marked increase of the curing salt diffusivities in the tissue was observed when the diffusion occurred in the presence of high NaCl concentration. This fact could not be explained by the Maxwell-Stefan theory that considers the diffusivity of the ionic species in multicomponent electrolyte solutions. However, penetration of high NaCl concentration in a tissue may affect irreversibly the cellular structure leading to higher diffusion coefficients.