Heat stability of skim milk containing various levels of micellar calcium phosphate

Summary

This study assessed thermal stability in micellar calcium phosphate (MCP)-adjusted skim milk samples containing 67 (MCP₆₇) or 113 (MCP₁₁₃) % of the MCP content of control milk (MCP₁₀₀) at 120 °C for 5 s or 140 °C for 1 s at pH 6.3, 6.6, 6.9 or 7.2. Sample MCP₆₇ exhibited the smallest heat-induced reduction in non-sedimentable individual caseins and whey proteins, and only limited heat-induced increases in particle size and turbidity. MCP₆₇ samples exhibited the highest levels of non-sedimentable k-casein post-heating, a key factor in heat coagulation. Sample MCP₁₁₃ displayed the strongest heat-induced decrease in non-sedimentable casein, coupled with the highest heat-induced increases in particle size and turbidity, suggesting comparatively lower thermal stability. Moreover, elevated MCP levels in MCP₁₁₃ samples might contribute to micelle instability. Milk pH at heating exhibited a linear correlation with heat stability. Overall, the findings emphasize the substantial influence of MCP and pH on heat-induced alterations in sterilized milk.