Biocompatible micro-gel particles from cross-linked casein micelles

Area of Science:

• Food science and technology
• Biochemistry
• Materials science

Background:

• Casein micelles are complex colloidal structures crucial in dairy products.
• Understanding their stability is key for food processing and material applications.
• Chemical agents like urea and citrate can destabilize native casein micelles.

Purpose of the Study:

• To investigate the stability of internally cross-linked casein micelles.
• To determine the effect of urea and trisodium citrate on these modified micelles.
• To explore the potential of cross-linked casein micelles as biocompatible micro-gel particles.

Main Methods:

• Casein micelles were cross-linked using transglutaminase.
• Turbidity, particle size, and micellar structure were analyzed using light scattering (dynamic and static) and small-angle neutron scattering.
• Model calculations were performed to interpret the experimental data.

Main Results:

• Urea and trisodium citrate treatments progressively reduced turbidity and increased particle size, indicating micellar swelling.
• Despite these changes, the cross-linked casein micellar network remained intact.
• Experimental data aligned with model calculations, confirming the stability of the covalently bound protein network.

Conclusions:

• Transglutaminase cross-linking confers significant stability to casein micelles against chemical disruption.
• The cross-linked protein network is resistant to urea and citrate.
• These findings support the use of cross-linked casein micelles as stable, biocompatible protein micro-gel particles.