Characterization of the interactions between chitosan/whey protein at different conditions

Abstract This research investigated the interaction between chitosan and whey protein molecules in terms of pH and heating. The FTIR, rheological analysis, turbidity, and zeta potential measurements were used to assess this interaction. At pH 4.0, addition of low amount chitosan with chitosan/whey protein isolate (C/WPI) ratio of 1:5 effectively prevented the denaturation of whey proteins after heating, whereas high amount of chitosan (C/WPI,1:2) led to depletion flocculation. The combination of chitosan and whey proteins was electrostatic attracting at pH 5.5 and 6.0. At low chitosan addition, the complexes formed at pH 5.5 showed higher viscosity and the complexes formed at pH 6.0 showed a shear-thinning behaviour. At high chitosan addition, the complexes showed high viscosity at pH 6.0. Heating led to the decrease of viscosity and increase of turbidity. The results manifested that chitosan and whey protein formed different complexes at pH 5.5 and 6.0, and the complexation of C/WPI was influenced by heating and ratio of chitosan and whey proteins.