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New controlled release systems produced by self-assembly of biopolymers and colloidal particles at fluid-fluid interfaces
Okra pectin obtained by hot buffer extraction (HBSS) consists of an unusual pectic rhamnogalacturonan I structure in which acetyl groups and alpha galactose residues are substituted on rhamnose residues within the backbone. The okra Chelating agent Soluble Solids (CHSS) pectin consists of slightly different structures since relatively more homogalacturonan is present within the macromolecule and the rhamnogalacturonan I segments carry slightly longer side chains. The rheological properties of both okra pectins were examined under various conditions in order to understand the unusual slimy behaviour of okra pectins. The viscosity of the okra HBSS pectin was 5-8 times higher than the viscosity of the okra CHSS pectin. The okra HBSS pectin showed an elastic behaviour (G' > G '') over a wide range of frequencies (10(-1)-10 Hz), at a strain of 10%, while okra CHSS and saponified okra HBSS/CHSS pectin showed predominantly viscous responses (G' < G '') over the same frequency range. The results suggest that the structural variation within the okra pectins greatly affect their rheological behaviour and it is suggested that acetylation of the pectin plays an important role through hydrophobic associations. Dynamic light scattering was used to study the association behaviour of both okra pectins at low concentration (0.001-0.1% w/w). Results showed that the saponified okra pectins did not exhibit a tendency to aggregate in the concentration range studied, whereas both non saponified samples showed a substantial degree of association. These results suggest that the unusual slimy behaviour of the non saponified samples may be related to the tendency of these pectins to associate, driven by hydrophobic interactions. (C) 2009 Elsevier Ltd. All rights reserved. [hide]
Scientific Board
Andreas Bausch
TU Munich, Germany ►
Peter Fischer
ETH Zurich, Switzerland ►
Anne-Marie Hermansson
SIK, Sweden ►
Martin Kroger
ETH Zurich, Germany/Switzerland ►
Erik van der Linden
Wageningen UR, The Netherlands ►
Niklas Loren
SIK, Sweden ►
Leonard Sagis
Wageningen UR, The Netherlands ►
Erich Windhab
ETH Zurich, Switzerland ►
Klaas-Jan Zuidam
Unilever, The Netherlands ►
Scientific Stuff
Manuela Duxenneuner
ETH Zurich, Switzerland ►
Sophia Fransson
SIK, Sweden ►
Nam-Phuong Humblet-Hua
Wageningen UR, The Netherlands ►
Joeska Husny
ETH Zurich, Australia/Switzerland ►
Orit Peleg
ETH Zurich, Israel/Switzerland ►
Cyrille Vezy
TU Munich, Germany ►
Varvara Mitropoulos
ETH Zurich, Switzerland ►
Associated Scientists
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SY Tee, AR Bausch, PA Janmey,
The mechanical cell
CURRENT BIOLOGY 19 (2009) R745 ►Selected conferences (co-)organized by project members
8th World Congress on Computational Mechanics WCCM8 2008
30 June - 5 July 2007, Venice, Italy ►13 May 2025
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