Diffusion of polyethyleneglycols in casein solutions and gels as studied by pulsed field gradient NMR.

Molecular transport characterized by diffusion coefficients is a key feature of food processes and especially in dairy processes. Caseins represent 80% of the protein content in milk and are directly involved in the formation of dairy gels. Consequently, providing a quantitative description of the solute diffusion in casein gels should contribute significantly to rationalization of the dairy processes. The objectives of this study were to study the self-diffusion coefficient of molecular probes [polyethyleneglycol (PEGs)] in casein solutions and gels, in particular with regard to the effects of the probe molecular size and casein concentration. We have shown that the PEG diffusion was an efficient tool to reveal the structural information relative to the gel matrix structure.