title: Modulating surface rheology by electrostatic protein/polysaccharide interactions.
abstract: There is a large interest in mixed protein/polysaccharide layers at air-water and oil-water interfaces because of their ability to stabilize foams and emulsions. Mixed protein/polysaccharide adsorbed layers at air-water interfaces can be prepared either by adsorption of soluble protein/polysaccharide complexes or by sequential adsorption of complexes or polysaccharides to a previously formed protein layer. Even though the final protein and polysaccharide bulk concentrations are the same, the behavior of the adsorbed layers can be very different, depending on the method of preparation. The surface shear modulus of a sequentially formed beta-lactoglobulin/pectin layer can be up to a factor of 6 higher than that of a layer made by simultaneous adsorption. Furthermore, the surface dilatational modulus and surface shear modulus strongly (up to factors of 2 and 7, respectively) depend on the bulk -lactoglobulin/pectin mixing ratio. On the basis of the surface rheological behavior, a mechanistic understanding of how the structure of the adsorbed layers depends on the protein/polysaccharide interaction in bulk solution, mixing ratio, ionic strength, and order of adsorption to the interface (simultaneous or sequential) is derived. Insight into the effect of protein/polysaccharide interactions on the properties of adsorbed layers provides a solid basis to modulate surface rheological behavior.
authors.affiliation: Wageningen Centre for Food Sciences, P.O. Box 557, 6700 AN Wageningen, The Netherlands. renate.ganzevles@wur.nl
authors.forename: Renate A
authors.initials: RA
authors.lastname: Ganzevles
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Zinoviadou
authors.forename: Ton
authors.initials: T
authors.lastname: van Vliet
authors.forename: Martien A
authors.initials: MA
authors.lastname: Cohen
authors.forename: Harmen H
authors.initials: HH
authors.lastname: de Jongh
mesh_terms: D000327:Adsorption; D000388:Air; D000818:Animals; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007782:Lactoglobulins / Q000737:chemistry; D009821:Oils / Q000737:chemistry; D010368:Pectins; D011134:Polysaccharides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012212:Rheology / Q000379:methods*; D055672:Static Electricity; D013499:Surface Properties; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: D007477:Ions; D007782:Lactoglobulins; D009821:Oils; D011134:Polysaccharides; D011506:Proteins; D014867:Water; D010368:Pectins