Protein and Salt Effects on Ca2+-Induced Cold Gelation of Whey Protein Isolate

Increasing whey protein concentration (from 6 to 10% w/v) decreased gel opacity but increased gel strength and water-holding capacity (WHC). Increasing CaCl₂, concentration (from 5 to 150 mM) increased gel opacity and gel strength at the high protein concentration (i.e., 10%). However, it lowered gel strength at protein concentration > 10%. Young's modulus and distance to fracture values indicated that gels were most rigid at 30 mM CaCl₂, at which point the extent of aggregation (measured by turbidity) was the highest. Increasing CaCl₂ concentration from 5 to 150 mM slightly affected the WHC of Ca²⁺-induced gels. Protein concentration was the major factor in determining fracture properties and WHC.