Properties of beta-lactoglobulin/alginate mixtures as a function of component ratio, pH and applied shear

The objective of this research was to establish effects of selected process parameters (component ratio, pH, shear) on the properties of alginate (Alg)/beta lactoglobulin (beta lg) mixtures. Effects were assessed by measuring apparent viscosity, particle size, zeta-potential, hydrophobicity and conformational changes (FTIR). Intrinsic viscosity and critical concentrations were also investigated. Intrinsic viscosity of individual Alg and beta lg solutions increased with pH. Shearing of Alg/beta lg mixtures resulted in greater apparent viscosity at pH 3 which declined proportional to increase in pH. Particle size and surface hydrophobicity were higher at pH 3 and directly related to Alg concentration. Shear induced changes were observed in the secondary structure of beta lg in the beta lg/Alg mixtures associated with beta-sheet conformations shifting from 1635.64 to 1633.71/cm and occurred-only at pH 5. Under certain conditions, application of shear could manipulate and create different structures from these two biopolymers. (C) 2015 Elsevier Ltd. All rights reserved.