title: Interfacial tension of aqueous biopolymer mixtures close to the critical point.
abstract: Proteins and polysaccharides, being the main constructional materials in many biological structures, have a limited compatibility in aqueous media. At sufficiently high concentrations, they form water-in-water emulsions. Interfacial tension is an important parameter in such systems since it is a controlling factor in the morphology development during processing. In this work a rheo-optical methodology, based on the analysis of small angle light scattering (SALS) patterns during fibril break-up, is used to study the interfacial tension of water-sodium caseinate-sodium alginate systems located close to and relatively far from the binodal. The interfacial tension close to the critical point was approximately 10(-8) N/m, and it increased considerably, to a value of up to 5.2 x 10(-6) N/m farther from the critical point. For the scaling of the interfacial tension with the density difference between the phases, a scaling exponent of 3.1 +/- 0.3 was found, in agreement with the critical mean-field scaling exponent of 3.
authors.affiliation: Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven, Belgium.
authors.forename: Y A
authors.initials: YA
authors.lastname: Antonov
authors.forename: P
authors.initials: P
authors.lastname: Van Puyvelde
authors.forename: P
authors.initials: P
authors.lastname: Moldenaers
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry*; D002627:Chemistry, Physical / Q000379:methods; D020723:Glucuronic Acid / Q000737:chemistry*; D006603:Hexuronic Acids / Q000737:chemistry*; D008027:Light; D008956:Models, Chemical; D055095:Optics and Photonics; D012212:Rheology / Q000379:methods; D012542:Scattering, Radiation; D014867:Water
chemical_list: D000464:Alginates; D001704:Biopolymers; D002364:Caseins; D006603:Hexuronic Acids; D014867:Water; D020723:Glucuronic Acid