Abstract: To investigate the effect of combined high pressure and thermal treatments on protein molecular structure, the changes in the structural root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration, the number of hydrogen bonds, solvent accessible surface area, volume, and secondary structure of β-lactoglobulin after treatment with combinations of different pressures (0.1, 300, and 600 MPa) and temperatures (300 and 330 K) or thermal treatment alone at 100 ℃ (0.1 MPa and 373.15 K) were evaluated using molecular dynamics simulation, and the effects of pressure and temperature on the above structural indicators were analyzed by partial least squares regression (PLSR). The results showed that thermal treatment at 100 ℃ damaged the protein’s structure more severely than the combined treatment of 600 MPa and 330 K. For the combined treatments, temperature affected the RMSD and the number of α-helix significantly, which respectively increased and decreased at 330 K. Pressure treatment could reduce the solvent accessible surface area and volume of the protein, thus making its structure more compact. The number of hydrogen bonds between proteins, β-sheet, random coil, and RMSF were significantly affected by the interaction between pressure and temperature. The pressure treatment at 300 MPa could stabilize structural damage caused by heat treatment to the protein. Therefore, molecular dynamics simulation confirmed that high pressure combined with heat treatment at a certain temperature was milder, causing less structural damage to proteins compared with thermal sterilization at 100 ℃.

Key words: high pressure; thermal treatment; molecular dynamics; β-lactoglobulin