Structural Characterization of Casein Micelles in Dairy Systems

Casein micelles are complex colloidal assemblies that stabilise calcium and phosphate in milk and underpin the physicochemical properties of dairy products. Structured as spherical particles typically 50–500 nm in diameter, micelles comprise four principal casein proteins—αs1-, αs2-, β- and κ-casein—in conjunction with colloidal calcium phosphate (CCP) nanoclusters. The internal organisation of these micelles arises from mineral bridges and hydrophobic interactions, while κ-casein residues on the surface confer steric stability and solubility. Advances in scattering techniques, electron microscopy and proteomics have revealed heterogeneous substructures, modular protein interactions and dynamic CCP distribution. This structural insight is critical for manipulating gelation, emulsification and nutrient delivery in cheese, yoghurt and novel dairy formulations. Recent efforts have focused on synthetic and recombinant approaches to reassemble micelle-like particles, probing how processing parameters such as pH, temperature and ionic strength influence assembly, size and internal architecture. An integrated structural perspective informs both fundamental understanding and practical innovations across global dairy research, from improving functional performance to developing animal-free dairy alternatives.

Research from Nature Portfolio

Recent studies have employed comparative proteomics to map the diverse protein entourage of casein micelles across multiple dairy species. Global profiling identified nearly 200 associated proteins, including interactions between caseins and major whey proteins, which collectively influence micellar stability and metabolic pathways. This cross-species analysis delineated two major clusters—ruminant versus non-ruminant—highlighting evolutionary variations in micellar composition and functional attributes. Insights into species-specific differences in casein–whey associations and post-translational modifications provide a framework for tailoring dairy streams to nutritional and functional targets.

Structural Characterization of Casein Micelles in Dairy Systems publication trend

The graph below shows the total number of articles in structural characterization of casein micelles in dairy systems across all publications each year (not limited to Nature Index journals).

Technical terms

Casein micelle: A colloidal aggregate of casein proteins and colloidal calcium phosphate that stabilises minerals in milk.

Colloidal calcium phosphate (CCP): Nano-scale mineral clusters that cross-link casein molecules within micelles.

Small-angle X-ray scattering (SAXS): A technique probing nanometre-scale structure by measuring X-ray scattering at small angles.

Ultra-small-angle neutron scattering (USANS): A neutron scattering method sensitive to larger length scales, used to characterise multi-scale structures in hydrated systems.

Reassembled casein micelles (RCM): Artificially formed micelle-like structures created by combining casein fractions with calcium and phosphate under controlled conditions.

References

1. Effect of temperature, pH and calcium phosphate concentration on the properties of reassembled casein micelles. Food Hydrocolloids (2024).
2. Proteomic analysis and cross species comparison of casein fractions from the milk of dairy animals. Scientific Reports (2017).
3. Investigating casein gel structure during gastric digestion using ultra-small and small-angle neutron scattering. Journal of Colloid and Interface Science (2021).
4. Engineering artificial casein micelles for future food: Is casein phosphorylation necessary?. Food Research International (2023).