Hydrostatic pressures (50-300 MPa) were applied at 0degC for 50 min to determine the aggregation and viscoelastic properties of tilapia (Orechromis niloticus) myosin fragments (subfragment-1 (S-1) and rod). With pressure treatment at <150-MPa, S-1 underwent intermolecular interaction to increase its elastic properties. After pressure treatment at 200 MPa, S-1 unfolded, aggregated and decreased its solubility. A turbid solution was obtained after pressurization at >200 MPa and, with increasingpressure, S-1 transformed to a more elastic gel. At 200 MPa, S-1 denatured entirely with no change of enthalpy detected by DSC. However, rod fragment properties did not change during pressurization. It is concluded that S-1 contributes to the initiation of gel formation in myosin, and that the role of the rod fragment is not clear.
