Aggregation in a concentrated model protein system: a mesoscopic simulation of β-casein self-assembly

A mesoscopic model of a concentrated system of amphiphilic co-polymer molecules has been investigated in three dimensions by Brownian dynamics computer simulation. Each co-polymer species consists of a flexible bonded chain of four hydrophilic segments and 12 hydrophobic segments. Equilibrium configurations have been generated as a function of the polymer volume fraction and the strengths of the hydrophobic and electrostatic segment–segment interactions. Some quantitative data are reported on segment co-ordination numbers, maximum aggregate sizes and diffusion coefficients. The mesoscopic simulation approach is put forward as a simple systematic way of modelling a solution of β-casein-like molecules under concentrated conditions. Subject to suitable modifications and refinements, this approach provides a framework for investigating effects of protein concentration and solution conditions on the structure of self-assembled casein systems in food gels and emulsions.