Properties of sodium caseinate film-forming dispersions and films.
The flow properties of sodium caseinate (NaCAS) film-forming dispersions were studied as a function of protein and glycerol concentration. Apparent viscosity vs. concentration profiles showed a disruption at about 10% (wt/wt) NaCAS. This was interpreted in terms of protein-water and protein-protein interactions. The presence of glycerol in the NaCAS film-forming suspensions reduced the viscosity of aqueous NaCAS as a consequence of decreasing protein-protein and protein-solvent interactions through the hydrogen bonding formation between the glycerol, the polypeptide chain of NaCAS, and water molecules. For higher concentration of glycerol, viscosity of NaCAS dispersions increased as a result of increasing total solid content. The glass transition temperature for solid films of 10% (wt/wt) NaCAS decreased with the glycerol content. The glycerol-protein interactions reduced the protein-protein interaction and, thus, increased the intermolecular spacing, leading to higher protein chain mobility and water vapor permeability.
Laboratoire de Physico-Chimie et Génie Alimentaires, Ecole Nationale Supérieure d'Agronomie et des Industries, Alimentaires, Institut National Polytechnique de Lorraine, Vandoeuvre Lès Nancy, Cedex France. khaoula.khwaldia@ensaia.inpl-nancy.fr
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D002364:Caseins / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004591:Electrophoresis, Polyacrylamide Gel; D018857:Food Packaging; D005990:Glycerol / Q000032:analysis / Q000737:chemistry; D006860:Hydrogen Bonding; D011506:Proteins / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014783:Viscosity; D014867:Water
D002364:Caseins; D011506:Proteins; D012997:Solvents; D014867:Water; D005990:Glycerol