The aggregation of whey proteins that was induced by CaCl2 was investigated by measuring turbidity and aggregate size. The effect of the aggregation on thermal gelation was determined by measuring gel hardness. Standard conditions were set at 10% whey protein solution, 20 mM CaCl2, and 45°C in order to observe the influence of different variable levels on the aggregation. The addition of 20 mM CaCl2 to a 10% whey protein isolate solution resulted in a continuous increase in turbidity during 5 h of incubation at room temperature (21°C). As expected, an increase in temperature (21 to 45°C) or CaCl2 concentration (5 to 50 mM) increased the rate and extent of the aggregation. Stable colloidal aggregates were formed with 10 to 30 mM CaCl2. An increase in protein concentration from 5 to 20% remarkably reduced the rate and extent of the aggregation during the 5-h incubation. The aggregation was dependent on the weight ratio of CaCl2 to whey proteins. Aggregation induced by CaCl2 before heat-induced gelation greatly affected the hardness of the gels that were formed by heat treatment (80°C for 30 min). The formation of the hardest gels required the optimal extent of aggregation or aggregate size.
All Science Journal Classification (ASJC) codes
- Food Science
- Animal Science and Zoology