1H NMR diffusometry study of water in casein dispersions and gels.
The self-diffusion coefficients of water in casein solutions and gels were measured using a pulsed-gradient spin-echo nuclear magnetic resonance technique (PGSE NMR). The dependence of the self-diffusion coefficient of water on the concentration and structure of casein is reported. The results were analyzed using a cell model. It was found that the water self-diffusion coefficient is insensitive to the structure of the casein in solution or in a gelled state. The influence of casein concentration on the water self-diffusion coefficient could be explained by obstruction from the casein molecule. Assuming a simple model with two water regions, each characterized by a specific water concentration and value of the water diffusion coefficient, the water mobility reduction induced by the casein can be rationalized.
Mariette
François
F
Cemagref, UR Technologie des Equipements Agro-alimentaires, CS 64426, 17 Avenue de Cucillé, 35044 Rennes, Cedex, France. francois.mariette@cemagref.fr
Topgaard
Daniel
D
Jönsson
Bengt
B
Soderman
Olle
O
D002364:Caseins / Q000737:chemistry*; D004058:Diffusion; D005782:Gels; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008433:Mathematics; D012996:Solutions; D013329:Structure-Activity Relationship; D014867:Water / Q000737:chemistry*
D002364:Caseins; D005782:Gels; D012996:Solutions; D014867:Water