Influence of mechanical properties of pectin films on charge density and charge density distribution in pectin macromolecule

The hydration and mechanical properties of citrus pectin films were examined in conditions relevant to those in the plant cell wall. The pectins used for this study varied in the degree of esterification (DE) (high or low) and charge distribution on the backbone (random or block). The hydration of t...

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Bibliographic Details
Published inColloid and polymer science Vol. 284; no. 3; pp. 301 - 308
Main Authors ZSIVANOVITS, G, MARUDOVA, M, RING, S
Format Journal Article
LanguageEnglish
Published Berlin Springer 01.12.2005
Springer Nature B.V
Subjects
Applied sciences
Charge density
Crosslinking
Deformation
Esterification
Exact sciences and technology
Hydration
Macromolecules
Mechanical properties
Natural polymers
Pectin
Physicochemistry of polymers
Starch and polysaccharides
Elastic modulus
Swelling
Tensile
Film
Rheology
Mechanical properties
Pectin
Experimental study
Cell wall
Medium effect
Ionic strength
Aqueous medium
Oside polymer
Counter ion
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Summary:The hydration and mechanical properties of citrus pectin films were examined in conditions relevant to those in the plant cell wall. The pectins used for this study varied in the degree of esterification (DE) (high or low) and charge distribution on the backbone (random or block). The hydration of the films was controlled in an osmotic pressure experiment using polyethylene glycol solutions (PEG 20000). Hysteresis tests at constant deformation rate (stress vs deformation) were used for investigating the mechanical behaviour of films. Mechanical and hydration properties of pectin films were examined as a function of charge density, charge density distribution and counterion environment--K^sup +^, Ca^sup 2+^, Mg^sup 2+^. Swelling decreased with increasing counterion concentration. The effect is stronger in the case of Ca^sup 2+^ and Mg^sup 2+^ for low esterified pectins and therefore crosslinks from divalent ions could be assumed. The crosslink effect is confirmed in mechanical experiments where an increase in the film tensile modulus is observed with increasing counterion concentration. It is shown for the first time that in case of highly concentrated pectin solutions Mg^sup 2+^ cations also act as a crosslinker for pectin macromolecules.[PUBLICATION ABSTRACT]
Bibliography:ObjectType-Article-1
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ISSN:0303-402X
1435-1536
DOI:10.1007/s00396-005-1378-2