Аннотация:β-lactoglobulin–oligochitosan (MW 9500 Da) system was studied under conditions of protein-polysaccharide incompatibility, the dipole-charge, and charge-charge protein-polysaccharide interactions at pH 3.0, 5.5, and 6.0, respectively, using ITC, DSC, and DLS. At pH 5.5 and 6.0, the ITC data revealed a complex formation between β-lactoglobulin and oligochitosan. The binding curves of the protein to the polysaccharide were obtained. The binding parameters, namely, the number of sites () and the binding constant (), were estimated in terms of the Langmuir equation. These are 2.8 ± 0.1 and = 106.4±0.1 M−1 at рН 5.5, while 1.5 ± 0.1 and = 105.6±0.1 M−1 at рН 6.0. At pH 3.0, when both the protein and polysaccharide are positively charged, the denaturation parameters of β-lactoglobulin in the β-lactoglobulin–oligochitosan system and in the absence of the polysaccharide coincide independently of the system composition. Under conditions of the complexation, the denaturation parameters of β-lactoglobulin (the denaturation temperature, enthalpy, entropy, and width) displayed complicated dependences on the oligochitosan content. Their analysis supported by measurements of the diffusion coefficients implied that the conformational stability of β-lactoglobulin in the β-lactoglobulin–oligochitosan complexes was defined by the complex composition and supramolecular structure of oligochitosan.