EFFECTS OF pH VALUES AND FAT CONTENT ON SODIUM CHLORIDE DIFFUSION RATE IN PORK

ABSTRACT Chloride diffusion was studied in pale, soft, exudative (PSE) pork meat of pH 5.4 to 5.5, normal-quality meat of pH 5.6 to 5.7 and dark, firm, dry (DFD) meat of pH 6.6 to 6.8, as well as in meat-fat batters of 10, 20 and 30% of fat. Cylindrical glass pipes filled with meat or batter were immersed into brine containing 16% NaCl and 0.16% NaNO2. After 24, 48, 72, 96, 120, 144 and 168 h of curing, chloride content in samples was measured and effective diffusion coefficient (Def) was calculated. Along with the decrease of pH of meat, sodium chloride content increased and higher Def was noted. Chloride concentration in the internal layer of PSE meat was about 80% higher compared with the normal-quality meat and about 130% higher than in DFD meat. Chloride Def decreased significantly with the increase of fat content in meat-fat batter. PRACTICAL APPLICATIONS Besides technological benefits of curing process in meat, excessive residues of the reacting curing ingredients can lead to the direct toxicological effects. Thus, there is a need to optimize the curing process in the direction to determine a precise dosage of the curing substances and appropriate time of curing which depends on the chemical composition of raw material as well as its biochemical condition. The results obtained in the study enabled to adjust the curing time of meat of different pH and fat content. Meat of lower pH should be cured shorter than normal-quality meat, whereas dark, firm, dry meat (high pH) should be cured longer. Fat content in raw meat also significantly affects the salt migration rate. With increase of fat content, the time of curing should be longer. The described findings might be helpful in designing the technological process.