Rheological properties of enzymatic milk gel: Effect of ion partitioning in casein micelles

Casein micelles (CMs) are colloids of ?150 nm diameter formed by the association milk proteins and minerals. Divalent cations, i.e. Ca2+ Mg2+, exist in two forms CMs: either directly bound to casein residues (C-bound) without inorganic phosphate, or a precipitated form called micellar calcium phosphate (MCP). The composition properties CMs vary with changes physicochemical conditions milk; e.g. after addition salt change pH. Moreover, rheological enzymatic gels known be strongly influenced variations mineral equilibria. We report this study on effect cation partitioning rheology gel. Firstly, salts acid (CaCl2, MgCl2, Na2HPO4, Na3Cit HCl) were added produce set 19 samples containing different proportions C-bound MCP order identify correlations parameters (G?, G?, tan?) resulting gels. Three milks then selected according content further characterized propose mechanisms that might explain dependence gel macroscopic those CMs. showed well correlated types cations present an increase raised values G? G? while lowered tan?. To these inter-dependencies, viewed as soft whose modulus could tuned their content. Consequently, contents would have differing abilities fuse aggregation, which appeared link microscopic attributes consistent manner. These results will useful understand complex produced dairy industry.