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The effect of freezing low-moisture Mozzarella before ripening on cheese microstructure and its relationship with caseins degradation and viscoelastic properties were analyzed, and results were compared with refrigerated control samples. Soluble and nonprotein nitrogen contents increased with ripening time although more rapidly in the samples that were frozen before ripening. Scanning electron microscopy (SEM) showed that freezing modified cheese microstructure due to ice formation; ice crystals weakened the casein matrix. Dynamic rheological tests were performed at 50 Њ Њ Њ Њ ЊC using oscillatory rheometry. G' increased with frequency and was higher for refrigerated than for samples frozen before ripening, at the same ripening times; G' diminished as aging time increased, although more rapidly for the samples frozen before ripening.

The objective of the present work was to analyze the effect of NaCl concentration on the diffusion coefficients of NaNO 2 and KNO 3 in pork tissue using unsteady techniques. Concentrations of nitrite and nitrate as a function of immersion time were determined in cylinders of meat using spectrophotometric techniques; experiments were performed at 4 o C and 20 o C. The unsteady state mathematical formulation was applied considering radial mass transfer. The diffusion coefficients were obtained fitting the theoretical curves to experimental data. An increase of the salt diffusivities in the tissue was observed when the diffusion occurred at high NaCl concentrations. This fact could not be explained by the Maxwell-Stefan theory. Penetration of high NaCl concentration in a tissue may affect the cellular structure leading to higher diffusion coefficients.

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