Effect of homogenisation pressure on the physical characteristics of artificial casein micelles

Artificial casein micelles (ACMs) were prepared through the remineralisation of sodium caseinate by addition of tripotassium citrate, dipotassium phosphate and calcium chloride. The particles obtained were comparable to native casein micelles in terms of apparent particle size, zeta potential, colour, colloidal stability, pelleted casein concentration, micellar hydration, buffering capacity and rennet coagulation behaviour. High pressure homogenisation (HPH) at up to 1000 bar significantly increased the whiteness of the samples and reduced particle size and polydispersity, and slightly increased absolute zeta potential. A considerable increase in rennet gel strength was measured following HPH at 200 bar, while samples homogenised at higher pressures (i.e., 600–1000 bar) generated weaker gels. HPH had no significant effect on ACMs in terms of pelleted casein, micelle hydration, micellar protein profile or buffering capacity. The results of this study advance our understanding of native casein micelle formation processes and the optimisation of functionality of ingredients derived therefrom.