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Modulation of the adsorption properties at air-water interfaces of complexes of egg white ovalbumin with pectin by the dielectric constant

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Author: Kudryashova, E.V. · Jongh, H.H.J.de
Type:article
Date:2008
Institution: TNO Kwaliteit van Leven · KvL
Source:Journal of Colloid and Interface Science, 2, 318, 430-439
Identifier: 240656
doi: doi:10.1016/j.jcis.2007.10.040
Keywords: Nutrition · Food technology · Air-water interface · Fluorescence · Pectin · Protein adsorption · Solvent quality · Surface tension · Absorption · Ethanol · Fluorescence · Permittivity · Proteins · Surface tension · Tensile testing · Air-water interface · Protein adsorption · Solvent quality · Interfaces (materials) · alcohol · egg white · ovalbumin · pectin · solvent · urea · water · adsorption · adsorption kinetics · air · anisotropy · article · circular dichroism · complex formation · dielectric constant · fluorescence · measurement · molecular dynamics · molecular interaction · priority journal · protein stability · protein structure · spectroscopy · surface tension · Adsorption · Air · Animals · Chickens · Egg White · Electrostatics · Ethanol · Fluorescence · Kinetics · Ovalbumin · Ovum · Particle Size · Pectins · Solutions · Surface Properties · Time Factors · Water

Abstract

The possibility of modulating the mesoscopic properties of food colloidal systems by the dielectric constant is studied by determining the impact of small amounts of ethanol (10%) on the adsorption of egg white ovalbumin onto the air-water interface in the absence and presence of pectin. The adsorption kinetics was monitored using tensiometry. The addition of ethanol resulted in considerably slower adsorption of the protein onto the interface, and this effect was enhanced when the protein was in complex with the pectin. Time-resolved fluorescence measurements demonstrated that in the case of noncomplexed ovalbumin the addition of ethanol resulted in a more condensed protein surface layer where ovalbumin adopted a preferred orientation at the interface. In contrast, the effect of ethanol on the ovalbumin-pectin complex suggested a pronounced multipoint electrostatic interaction between protein and polyelectrolyte and the formation of a more rigid spatial arrangement within the complex, thereby leading to suppressed protein-protein interactions. From this work it is concluded that by the enhanced binding affinity between ovalbumin and pectin a strong effect on the adsorption properties of the protein can be accomplished. This work does therefore illustrate how solvent quality can be exploited effectively to enhance or suppress protein functional behavior in complex applications containing air-water interfaces. © 2007 Elsevier Inc. All rights reserved. Chemicals / CAS: alcohol, 64-17-5; egg white, 9006-50-2; ovalbumin, 77466-29-6; pectin, 9000-69-5; urea, 57-13-6; water, 7732-18-5; Ethanol, 64-17-5; Ovalbumin, 9006-59-1; pectin, 9000-69-5; Pectins; Solutions; Water, 7732-18-5