The effect of dephosphorylation and succinylation on the properties of casein proteins adsorbed to the surface of latex particles

摘要

Dephosphorylation decreased the absolute zeta potential and diameters of alpha(S1)-casein-coated latex particles. Similar effects were observed for alpha(S1)-casein dephosphorylated prior to or after adsorption. If alpha(S1)-casein adopts a loop arrangement at hydrophobic surfaces, then it appears that dephosphorylation causes the loop to move closer to the surface. Dephosphorylation caused a larger change for particles coated with alpha(S1)-casein than beta-casein, whereas small changes were observed for kappa-casein, consistent with the phosphorylation levels of these caseins. Succinylation increased the absolute value of zeta potential and the diameters of alpha(S1)-casein-coated latex particles. A higher level of succinylated alpha(S1)-casein was required to saturate the particle surface. It is proposed that succinylated alpha(S1)-casein has the C-terminal region adsorbed to the particle surface and N-terminal region extending from the surface as a hair. Results of this study help explain the effect of dephosphorylation and succinylation on the functional properties of the caseins, particularly in stabilising emulsions. (C) 2019 Elsevier Ltd. All rights reserved.