The interaction of casein micelles with κ-carrageenan studied by diffusing wave spectroscopy

The light-scattering properties of mixtures of skim milk and κ-carrageenan in the concentration range 0–0.1% w/v have been studied in detail. The use of diffusing wave spectroscopy (DWS) permitted the study of undiluted mixtures of skim milk and polysaccharide. The results appear to show that the movement of the casein micelles in the mixtures at 25 °C depends on the formation of carrageenan/casein gels, but that within the gels, the casein micelles themselves have considerable mobility. Different methods of mixing milk and carrageenan did not affect the overall conclusions, although the errors of measurement depended on the methods of mixing. Heat treatment of the milk to denature the whey proteins appeared to have no effect on the interactions of the particles and polysaccharides.