Structure of Biomimetic Casein Micelles: Critical Tests of the Hydrophobic Colloid and Multivalent-Binding Models Using Recombinant Deuterated and Phosphorylated β -Casein

•Recombinant, deuterated, in vivo phosphorylated β-casein was produced.•Biomimetic casein micelles were produced and characterised.•κ-Casein was shown to be distributed throughout the casein micelle.•Findings agree with the multivalent-binding model, not the hydrophobic colloid models.•Casein micelle acts a mineral and protein chaperone in the mammary gland.