Combined effect of CaCl2 and high pressure processing on the solubility of chicken breast myofibrillar proteins under sodium-reduced conditions

The combined effect of calcium chloride (CaCl2) (20-100 mM) and high pressure processing (HPP, 200 MPa) on the solubility of myofibrillar proteins (MP) was investigated under sodium-reduced conditions (0.3 M sodium chloride). The results revealed that HPP combined with low concentrations (<40 mM) of CaCl2 synergistically increased the solubility of MP, but an antagonistic effect occurred when a high concentration (100 mM) of CaCl2 was present. This synergistic effect could be attributed to a mildly destabilized conformation of myosin, an increased surface hydrophobicity and the decreased total sulfhydryl group content of MP. However, CaCl2 at 100 mM destabilized myosin to a larger extent and induced non-disulfide covalent cross-linking of S-1 subfragment in pressurized MP, thus attenuating the solubilizing effect of HPP on the myosin heavy chain, resulting in the antagonistic effect. Therefore, HPP in combination with low-level CaCl2 (<40 mM) may improve the functional properties of sodium-reduced meat products.