Influences of saccharides on the pressure-induced gels from a whey protein isolate

The influence of saccharides on the pressure-induced gel (800 MPa, 10 min, 30degreesC) from a 20% (w/v) whey protein isolate (WPI) solution was investigated for various concentrations of lactose (0-20%) or 10% glucose at various pH values. The addition of lactose increased the protein solubility and water-holding capacity, decreased the rheological properties, and changed the microstructure of the WPI gel. Glucose had a more significant effect on the rheological properties and water-holding capacity of the pressure-induced gel from the WPI at acidic and neutral than at alkaline pH values, whereas the protein solubility was higher at neutral and alkaline than at acidic pH values. The addition of saccharides weakened the protein-protein interaction under hydrostatic pressure, its effect being related to the pH value of the initial WPI solution.