28-2 |
Effect of salt on structure-function relationships of cheese |
A. J. PASTORINO1, C. L. Hansen, and D. J. McMahon. (1) Nutrition & Food Sciences, Utah State Univ., Western Dairy Center, 8700 Old Main Hill, Logan, UT 84322 Changes in cheese structure may help explain the effect of chemical composition on cheese functionality. Our objective was to determine the effect of salt on structural and functional properties of cheese. Unsalted, commercial Muenster cheese (41% moisture, 29% fat, 0.7% calcium) was obtained on 1 d and cut into 0.5 to 0.6-kg blocks that were vacuum packaged and stored for 14 d at 4°C. Cheese blocks were then high-pressure injected 1, 3, or 5 times, with a 20% (wt/wt) sodium chloride solution. Successive injections were performed 24 h apart. After 40 d of storage at 4°C, cheese blocks were analyzed for chemical, structural, and functional attributes. Injecting sodium chloride increased the salt content of cheese. After 5 injections, the salt content was 2.7% compared to 0.1% in the control, uninjected cheese. At the highest levels, salt injection promoted syneresis, and residual moisture was observed inside cheese packages. After 3 injections the moisture content decreased from 41% to 39%. However, the increased salt content resulted in a net weight gain of 1.9% after 5 injections. Cheese pH, soluble nitrogen, and total and soluble calcium content were unaffected. Although only significant at P < 0.1, cheese injected 5 times had a 4% increased area of cheese matrix occupied by protein compared to uninjected cheese. Cheese hardness, adhesiveness, and initial rate of cheese flowing increased upon salt injection. However, the final extent of cheese flow was unaffected. Adding salt to cheese alters protein interactions, such that the protein matrix becomes more hydrated and expands. However, increasing the salt content of cheese did not cause an exchange of calcium with sodium. Therefore, calcium-induced protein interactions would remain the limiting factor controlling cheese functionality.
Session 28, Dairy Foods: Developments in microbiology and chemistry of cheese
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