Effect of ultra-high pressure on the structure and gelling properties of low salt golden threadfin bream (Nemipterus virgatus) myosin

The effects of ultra-high pressure (UHP) treatment (150–600 MPa for 5 min) on the conformation and related gelation properties of golden threadfin bream (Nemipterus virgatus) myosin with two different NaCl concentrations (0.3 moL/L and 0.6 moL/L) were investigated. Upon increases in pressure (0.1–600 MPa), myosin unfolded from α-helical to a β-sheets, and buried hydrophobic and sulfhydryl groups became exposed. Therefore, the surface hydrophobicity and the reactive sulfhydryl content increased for both NaCl concentrations. The rheological modulus of groups in a low NaCl concentration (0.3 moL/L) reached a maximum value of 150 MPa, but decreased upon further increases in pressure (300–600 MPa); a similar tendency was also observed in the 0.6 moL/L NaCl groups. Low-field pulsed nuclear magnetic resonance and scanning electron microscopy results with the low NaCl groups indicated that moderate UHP treatment (≤300 MPa) strengthened the water retention and structure properties of the myosin gel, while stronger UHP treatment (≥450 MPa) weakened them. This undesirable effect of excess UHP treatment was somewhat mitigated in the 0.6 moL/L concentration groups. These findings show the potential use of UHP treatment in improving the gelling properties of myosin at low salt concentrations.