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Enzymatically and chemically de-esterified lime pectins: characterisation, polyelectrolyte behaviour and calcium
M C Ralet1, V Dronnet, H C Buchholt
1Unité de Recherche sur les Polysaccharides, leurs Organisations et Interactions, Institut National de la Recherche Agronomique, rue de la Géraudière, B.P. 71627, F-44316 Cedex 3, Nantes, France. ralet@nantes.inra.fr
Carbohydrate Research
|November 2, 2001
Summary
This study modified pectin
Area of Science:
- Biochemistry
- Polymer Science
Background:
- Pectin's properties are influenced by methyl esterification.
- Understanding pectin's behavior is crucial for food and pharmaceutical industries.
Purpose of the Study:
- To investigate the impact of de-esterification on pectin's physicochemical properties.
- To analyze calcium binding in chemically and enzymatically modified pectins.
Main Methods:
- Pectin de-esterification using acid, alkali, and pectin methyl esterases.
- Determination of intrinsic pK values and counterion fractions.
- Comparison of experimental calcium binding data with Manning's theory.
Main Results:
- A unique intrinsic pK value of 2.90+/-0.15 was determined for pectin.
- De-esterification method influenced pK(a) variations with ionization degree.
- Experimental calcium binding correlated with theoretical values, suggesting pectin dimerization.
Conclusions:
- Pectin de-esterification significantly alters its ionization and calcium binding characteristics.
- A blockwise carboxyl group distribution promotes pectin dimerization in the presence of calcium.
- Findings provide insights into pectin structure-function relationships.
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