Complex coacervation of chitosan and soy globulins in aqueous solution: a electrophoretic mobility and light scattering study

Summary The effect of pHs and heating on the protein–polysaccharide complexation between the 0.5 wt% soy globulin (7S or 11S) and 0.1 wt% chitosan was studied. Electrophoretic and light scattering techniques were used to examine the electrical charge and aggregation of the individual biopolymers and complexes. At pH 3.0–6.5, 7S (or 11S) globulin in the presence of chitosan had significantly higher ζ-potentials and lower particles size than 7S (or 11S) globulin alone did (e.g. 600–6000 nm at pH 5.5), indicating the formation of complexes. After heating 7S (or 11S)–chitosan mixtures had higher positive value of ζ-potential. 7S (or 11S)–chitosan mixtures exhibited a significant increase in positive value of ζ-potential and stability after heating at lower pH values (pH 3.3 instead of pH 4.5). Compared with other mixtures, at pH 2.5–6.0, the most remarkable decrease in aggregation was obtained for 11S–chitosan mixtures after heating at pH 3.3.