Formation and characterization of the complex coacervates obtained between lactoferrin and sodium alginate.

The aim of this study was to evaluate the influence of some parameters (pH, NaCl, and ratio of biopolymers) on the formation of the complex coacervates of lactoferrin and sodium alginate. Different ratios of lactoferrin:sodium alginate were tested (1:1, 1:2, 1:4,1:8, 2:1, 4:1, and 8:1) at pH levels ranging from 2.0 to 7.0 with different concentrations of NaCl (0, 50, 100, 150, and 200 mM). Sodium alginate has a molecular weight of 138 kDa ± 0.07. The ratio of 8:1(lactoferrin: sodium alginate) at a pH of 4.0 with a low salt concentration was the optimal condition for the formation of the complex. The thermodynamic parameters demonstrated that the interaction between lactoferrin and sodium alginate was exothermic and spontaneous with a favorable enthalpic and unfavorable entropic contribution during the interaction. The chemical, thermal and morphological characteristics of the biopolymers and the complex coacervates demonstrated their nature and changes due to electrostatic interactions. The formation of complex coacervates between lactoferrrin and sodium alginate can serve as an alternative to the incorporation of lipophilic functional ingredients sensitive to high temperatures in various food systems.