Effects of high pressure on rheological properties of soy protein gels

Hydrated soy concentrate of 80% moisture content was subjected to pressures of 200, 400, 600 and 800 MPa at 20 and 60 °C for 20 and 50 min. The treated samples were subsequently analysed for viscoelastic behaviour and nitrogen solubility and their SDS-PAGE electrophoretic patterns were recorded. It was found that the rheological properties were more affected by temperature than pressure. The shape of the G′ and G″ data, as a function of frequency, changed little with temperature and/or pressure treatment. The chemical studies suggest that some limited disulphide bond formation occurs in temperature- and pressure-induced gel systems.