<p>This study examines the effects of calcium (Ca²⁺) and magnesium (Mg²⁺) ions on the physical properties and protein composition of sodium caseinate (NaCas) solutions during thermal processing. Using various analytical methods, including spectrophotometry, dynamic light scattering (DLS), LUMisizer, and high-performance liquid chromatography (HPLC), we assessed soluble protein content, ionic presence in the serum phase, particle size, dispersion stability, and protein profiling. Our findings reveal that calcium significantly reduces NaCas solubility beyond 12&#xa0;mM, precipitating α and β caseins, while magnesium has a milder effect, slightly altering αs1-casein solubility even at 15&#xa0;mM. Both ions exhibited similar binding patterns in the serum phase, forming aggregates of varying densities and sizes. Particle size and dispersion analyses indicated aggregation without cross-linking or gelation within the NaCas matrix. The findings highlight the intricate influence of divalent cations on the physical properties and protein characteristics of heat-treated NaCas, with significant implications for the development of NaCas-enriched dairy nutritional products.</p>