Print Email Facebook Twitter Molecular details of ovalbumin-pectin complexes at the air/water interface: A spectroscopic study Title Molecular details of ovalbumin-pectin complexes at the air/water interface: A spectroscopic study Author Kudryashova, E.V. Visser, A.J.W.G. van Hoek, A. de Jongh, H.H.J. TNO Kwaliteit van Leven Publication year 2007 Abstract To stabilize air-water interfaces, as in foams, the adsorption of surface-active components is a prerequisite. An approach to controlling the surface activity of proteins is noncovalent complex formation with a polyelectrolyte in the bulk phase. The molecular properties of egg white ovalbumin in a complex with pectin in the bulk solution and at air/water interfaces were studied using drop tensiometry (ADT) and time-resolved fluorescence anisotropy techniques. The complex formation of ovalbumin with pectin in the bulk resulted in the formation of a compact structure with a different spatial arrangement depending on the protein/pectin ratio. Complex formation did not provide an altered protein structure, whereas the conformational stability was slightly increased in the complex. In excess pectin, an overall condensed complex structure is formed, whereas at limited pectin concentrations the structure of the complex is more "segmental" . The characteristics of these structures did not depend on pH in the 7.0 to 4.5 regime. Interaction with pectin in the bulk solution resulted in a significantly slower adsorption of the protein to the air/water interface. The limited mobility of the protein at the interface was found for both ovalbumin and ovalbumin-pectin complexes. From both the rotational dynamics and total fluorescence properties of the protein in the absence and presence of pectin, it was suggested that the complex does not dissociate at the interface. Ovalbumin in the complex retains its initial "aqueous" microenvironment at the interface, whereas in the absence of pectin the microenvironment of the protein changed to a more nonpolar one. This work illustrates a more general property of polyelectrolytes, namely, the ability to retain a protein in its microenvironment. Insight into this property provides a new tool for better control of the surface activity of complex biopolymer systems. © 2007 American Chemical Society. Subject Food technologyAnisotropyComplexationInterfaces (materials)Molecular dynamicsPolyelectrolytesSpectroscopic analysisComplex biopolymer systemsFluorescence propertiesPectin concentrationsProteinsovalbuminpectinarticlechemistryinfrared spectrophotometryphase transitionultraviolet spectrophotometryOvalbuminPectinsPhase TransitionSpectrophotometry, InfraredSpectrophotometry, Ultraviolet To reference this document use: http://resolver.tudelft.nl/uuid:40f9994e-b870-46f6-bb1f-46299aed733a DOI https://doi.org/10.1021/la700379m TNO identifier 240091 ISSN 0743-7463 Source Langmuir, 23 (15), 7942-7950 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.