Controlling denaturation and aggregation of whey proteins during thermal processing by modifying temperature and calcium concentration

Whey protein isolate solutions (8.00g protein/100g; pH 6.8) were treated for 2min at 72, 85 or 85 degrees C with 2.2mM added calcium Ca to produce four whey protein systems: unheated control (WPI-UH), heated at 72 degrees C (WPI-H72), heated at 85 degrees C (WPI-H85) or heated at 85 degrees C with added Ca (WPI-H85Ca). Total levels of whey protein denaturation increased with increasing temperature, while the extent of aggregation increased with the addition of Ca, contributing to differences in viscosity. Significant changes in Ca ion concentration, turbidity and colour on heating of WPI-H85Ca, compared to WPI-UH, demonstrated the role of Ca in whey protein aggregation.