Rheological properties and characterization of polymerized whey protein isolates

Whey protein polymers were formed by heating whey protein isolate solutions at 80 degrees C. Flow behaviors of whey protein polymers produced from different protein concentrations and heating times were comparable to various flow behaviors of hydrocolloids. Polymer formation was found to be a two-phase process. The initial protein concentration was a significant factor that determines the size and/or shape of the primary polymer in the first phase as shown by intrinsic viscosity. Heating time was a factor in determining the aggregation in the second phase as shown by apparent viscosity. Intrinsic viscosity of whey protein polymers was as high as 141.7 +/- 7.30 mL/g, compared to 5.04 +/- 0.20 mL/g for native whey proteins. The intrinsic viscosity and gel electrophoresis data suggested that disulfide bonds played an important role in whey polymer formation.