Mild alkalinity preheating treatment regulates the heat and ionic strength co-tolerance of whey protein aggregates

A major obstacle to the use of whey protein in protein-enriched sports beverages is the heat-induced gelation of the protein in the presence of salt. In this study, whey protein soluble aggregates (WPSAs) with high tolerance to NaCl and heat were successfully generated by preheating whey protein isolate (WPI) at a low concentration (1 % w/v) and pH 8.5. The suspension of WPSAs (5 % w/v) with 100 mM NaCl maintained clarity, transparency, and good flowability even after 30 min of heating at 100 °C. However, suspensions prepared by untreated WPI turned into milky white gels. WPSAs had a reduced Zeta potential at pH 7 compared to WPI, making them more resistant to the electrostatic screening caused by NaCl. Additionally, WPSAs exhibited reduced sensitivity to heat treatment due to a more compact structure achieved through preheating modification. In light of these findings, a straightforward and effective method was presented for regulating the heat and ionic strength tolerance of whey protein aggregates.