Changes in myofibrillar proteins interactions and rheological properties induced by high-pressure processing

Response surface methodology was used to study the effect of pressure (0-600 MPa) and time (0-1,800 s) on the surface hydrophobicity, reactive sulphydryl groups content and the flowing properties of bovine myofibrillar proteins in solution at 10 g/l. Results show that high-pressure treatment induced a threefold increase of the surface hydrophobicity of myofibrillar proteins between 0 MPa and 450 MPa. The same upward trend was obtained on the reactive sulphydryl groups, which climbed from 40 to 69%. Concerning rheological properties of solutions, the flow index tended towards a maximum value close to the Newtonian behaviour (n=1), whereas the viscosity coefficient decreased with the increase of pressure. The statistical analysis of responses proves that pressure and its quadratic effect are the most important significant effects in comparison with the effects of time. Changes in myofibrillar proteins interactions and rheological properties are related to a structure change of the proteins, and could induce better functional properties.