Colloidal Properties of Casein Micelles at Threefold and Natural Concentrations upon Calcium or Chelator Addition: Implications for Binding of Water and Calcium

Understanding the behavior of casein micelles (CMs) in a concentrated state is of interest for the targeted functionalization of micellar casein concentrates (MCCs). We assessed potential differences in colloidal properties of CM at threefold (MCC) and milk-like concentration (MLC) in response to compositional changes of CM caused by modifications of the ionic environment induced by the addition of CaCl2 and trisodium citrate (TSC). CMs were therefore analyzed regarding surface charge, particle size distribution, volume fraction, and voluminosity. CMs in MCC showed less pronounced colloidal changes induced by TSC and CaCl2 than equally treated MLC. New mechanistic insights into structural integration and release of water and calcium in or from the micellar structure relative to the observed colloidal changes could be gained. This study offers a better comprehension of the properties of CM in the concentrated state and options for a more targeted design of their functionalities.