Quantitative multivalent binding model of the structure, size distribution and composition of the casein micelles of cow milk

Compatible theories describing the size distribution of milk casein micelles, the partition of milk salts and the formation of calcium phosphate nanocluster complexes are combined to provide the first quantitative model of the cow casein micelle. Complexes of caseins with calcium phosphate nanoclusters associate with each other and the remaining (free) caseins to form a stable, polydisperse distribution of micelle sizes. The micelles in the distribution have a highly hydrated coat-core structure in which the calcium phosphate nanoclusters, and caseins bound directly to them, occur only in the core whereas the free caseins are found in both the coat and core. The theory is used to describe the structure, substructure, surface potential, size distribution, and the salt and protein composition of casein micelles in a standard cow milk. Multivalent casein–casein interactions through short, linear, amino acid sequence motifs determine many aspects of casein micelle formation and stability.