Heat-induced changes of milk protein concentrate suspensions as affected by addition of calcium sequestering salts and shearing

Summary

Calcium sequestering salts (CSS) such as disodium hydrogen phosphate (DSHP) and trisodium citrate (TSC) can be used to improve the heat stability and solubility of milk proteins during thermal processing. Shearing is also an inherent part of food processing that can alter protein properties and functionality. The heat stability of milk proteins was investigated under combined temperatures (90 °C/5 min; 121 °C/2.6 min) and shear (100, 1000, 1500 s⁻¹) with 10, 20, or 30 mM DSHP or TSC. The calcium-binding capacity of individual CSS predominantly determined the impact of shear. With DSHP, the effect of shear was more pronounced at high temperatures and shear rates than with TSC. The significant influence of shear on casein micelles in DSHP-containing dispersions suggested that DSHP's lower calcium binding affinity minimised micellar disruption and led to a pronounced shear impact. Shear combined with heat considerably impacts the milk system in the presence of CSS.