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Interchain heterogeneity of enzymatically deesterified lime pectins
Marie-Christine Ralet1, Jean-François Thibault
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 Nantes Cedex 3, France. ralet@nantes.inra.fr
Biomacromolecules
|September 10, 2002
Summary
This study reveals how pectin
Area of Science:
- Food Science
- Biochemistry
- Polymer Chemistry
Background:
- Pectins are complex polysaccharides crucial in food texture.
- Methyl esterification (DM) significantly influences pectin properties.
- Understanding pectin de-esterification is key for food applications.
Purpose of the Study:
- To investigate the impact of different pectin methylesterases (PMEs) on pectin structure.
- To analyze the distribution of free carboxyl groups and its effect on calcium binding.
- To differentiate between fungal and plant PME mechanisms.
Main Methods:
- Production of pectins with varying DM using fungal and plant PMEs.
- Size exclusion chromatography (SEC) for molar mass separation.
- Ion exchange chromatography (IEC) for charge density analysis.
- Investigation of calcium binding properties.
Main Results:
- SEC revealed variations in composition and DM across fractions.
- IEC showed narrow charge distribution for fungal PME (multichain) vs. broad for plant PME (processive).
- Interchain DM polydispersity did not affect calcium binding.
- Plant PME's unique intrachain esterification pattern influences dimerization.
Conclusions:
- Fungal and plant PMEs exhibit distinct de-esterification mechanisms.
- Pectin's calcium binding is independent of interchain DM heterogeneity.
- Plant PME's processive mechanism leads to specific intrachain structures affecting dimerization.