Effects of structuring and destructuring anionic ions on the rheological properties of thermally induced beta-lactoglobulin gels

The effects of increasing levels (0-1.0 mol/dm(3)) of protein-structuring (chloride, NaCl; sulfate, Na(2)SO(4)) and -destructuring anionic ions (thiocyanate, NaSCN) on rheological properties and electron microstructures of protein gels were examined. The effects of the ions varied with concentration and species. At concentrations above 100 mM they enhanced gel strength in the order SCN(-) > Cl(-) > SO(4)(2-). The hardness of gels increased with increasing concentrations up to 0.1, 0.2 and 1.0 mol/dm(3) with SO(4)(2-), Cl(-) and SCN(-) respectively. Electron microstructures of the gels showed that distribution of the protein in the gel matrix became less ordered with increasing ion concentration.