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

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 zeta-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 zeta-potential. 7S (or 11S)-chitosan mixtures exhibited a significant increase in positive value of zeta-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.