title: Flexibility and Charge of Solutes as Factors That Determine Their Diffusion in Casein Suspensions and Gels.
abstract: This work explores the influence of both the physicochemical characteristics of solutes and the solute-matrix interactions on diffusion in casein systems. Diffusion coefficients of three solute groups (dextrans, proteins, and peptides) presenting different physicochemical characteristics, such as molecular flexibility and charge, were measured using the technique of fluorescence recovery after photobleaching (FRAP). The casein systems had the same casein concentration, but different microstructures (suspension or gel), and/or a different pH (5.2 or 6.6). Flexible solutes diffused more rapidly through the casein systems than the rigid ones. Electrostatic interactions between charged solute molecules and the casein matrix were partly screened due to the high ionic strength of the systems. As a consequence, it was the flexibility of the solute molecule (rather than its charge) that most influenced its diffusion through casein systems.
authors.affiliation: †INRA, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.|‡Agrocampus Ouest, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.
authors.forename: Juliana V C
authors.initials: JV
authors.lastname: Silva
authors.affiliation: †INRA, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.|‡Agrocampus Ouest, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pezennec
authors.affiliation: †INRA, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.|‡Agrocampus Ouest, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Lortal
authors.affiliation: †INRA, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.|‡Agrocampus Ouest, UMR1253 Science and Technology of Milk and Eggs, F-35042 Rennes, France.
authors.forename: Juliane
authors.initials: J
authors.lastname: Floury
mesh_terms: D002364:Caseins / Q000737:chemistry*; D055598:Chemical Phenomena; D003911:Dextrans / Q000737:chemistry*; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D005782:Gels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010455:Peptides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D013535:Suspensions / Q000737:chemistry
chemical_list: D002364:Caseins; D003911:Dextrans; D005782:Gels; D010455:Peptides; D011506:Proteins; D013535:Suspensions
keywords: casein; charge; diffusion; flexibility; solutes