Effects of high pressure modification on conformation and gelation properties of myofibrillar protein

The effects of high pressure (HP) treatment (100-500 MPa) on conformation and gelation properties of myofibrillar protein (MP) were investigated. As pressure increased (0.1-500 MPa), α-helix and β-sheet changed into random coil and β-turn, proteins unfolded to expose interior hydrophobic and sulfhydryl groups, therefore surface hydrophobicity and formation of disulfide bonds were strengthened. At 200 MPa, protein solubility and gel hardness reached their maximum value, particle size had minimum value, and gel microstructure was dense and uniform. DSC data showed that actin and myosin completely denatured at 300 MPa and 400 MPa, respectively. Rheological modulus (G′ and G″) of HP-treated MP decreased as pressure increased during thermal gelation. Moderate HP treatment (≦200 MPa) strengthened gelation properties of MP, while stronger HP treatment (⩾300 MPa) weakened the gelation properties. 200 MPa was the optimum pressure level for modifying MP conformation to improve its gelation properties.