Structural rearrangement of β-lactoglobulin induced by preheating and high hydrostatic pressure: Comparative effects on salt-thermal stability

β-Lactoglobulin (β-lg), the predominant whey protein fraction, is highly susceptible to aggregates under combined salt and thermal stresses, limiting its application in electrolyte-rich beverages. This study compared the preheating and high hydrostatic pressure (HHP) on improving the thermal stability of β-lg in systems containing NaCl and CaCl₂. Both treatments may modify β-lg, characterized by enhanced sulfhydryl oxidation, disulfide bond formation, carboxyl group exposure, and surface charge. The absolute ζ-potential increased from 17.3 to 20.3 mV after HHP at 600 MPa and to 21.9 mV after preheating at 120 °C, accompanied by decreases in sulfhydryl content from 48.2 to 36.0 and 19.0 μmol/g protein, respectively. These properties increased the thermal stability of β-lg and enhanced its resistance to ion-promoted aggregation. This work provided mechanistic insights into the regulation of salt and heat-induced aggregation of β-lg and offered a clean-label strategy to improve protein stability in electrolyte-rich beverage formulations.