Sodium Chloride Effect on Meat Tissue Microstructure as Measured by Diferential Scanning Calorimetry and Diffusion Coefficients

PINOTTI, A; CALIFANO, A; ZARITZKY, N

Valencia, España

Congreso; : III Congreso Iberoamericano de Ingeniería de Alimentos y I Congreso Español de Ingeniería de Alimentos; 2001

The objectives of the present work were: a) to determine the diffusion coefficients (Dm) of NaCl in pork tissue using brine solutions at 4°C from NaCl measurements as a function of time and fitting the theorical curves of the diffusional model to experimental data; b) to establish the effect of NaCl concentration on Dm, tissue microstructure (Scanning Electron Microscopy SEM) and protein denaturation (Differential Scanning Calorimetry DSC). A transient radial diffusion system was adopted using cylinders of Longissimus dorsi that were immersed in brines of different concentrations (1, 7, 14 and 33%). The mass of NaCl was determined using a Chloride Electrode.  DSC thermograms of tissue samples were recorded; three major peaks for untreated samples were observed corresponding to myosin (I and II, 58°C), sarcoplasmic protein and collagen (II, 65°C) and actin (III, 80°C). When the tissue was treated with increasing NaCl concentrations these peaks reduced their sizes and temperatures changed, due to protein denaturation. An increase of Dm was observed at high NaCl concentrations, that was interpreted by SEM  micrographs, DSC results and the changes in water holding capacity, because NaCl penetration affects cellular structure of the tissue. These induced changes could explain the high measured diffusion coefficients