title: Influence of chain length and polymer concentration on the gelation of (amidated) low-methoxyl pectin induced by calcium.
abstract: The gelation of low-methoxyl pectin (LMP) induced by addition of Ca2+ was studied by measuring the storage modulus as a function of temperature during cooling. Samples with different molar masses were prepared by mechanical degradation. The effect of the molar mass and the pectin concentration on the gelation properties was investigated. The effect of partial amidation was studied by comparing LMP and partially amidated LMP with the same molar mass and degree of methylation. The results are compared to those from a model developed for Ca2+-induced pectin gelation, and good agreement is found except at low concentrations and low molar masses where the gels are weaker than predicted. At low concentrations intrachain bonding weakens the gel, while the presence of small pectin chains weakens the gel because it neutralizes binding sites on larger chains.
authors.affiliation: Polymères, Colloïdes, Interfaces, UMR CNRS, Université du Maine, 72085 Le Mans, Cedex 9, France.
authors.forename: François
authors.initials: F
authors.lastname: Capel
authors.forename: Taco
authors.initials: T
authors.lastname: Nicolai
authors.forename: Dominique
authors.initials: D
authors.lastname: Durand
authors.forename: Patrick
authors.initials: P
authors.lastname: Boulenguer
authors.forename: Virginie
authors.initials: V
authors.lastname: Langendorff
mesh_terms: D000577:Amides / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D001703:Biophysics / Q000379:methods; D002118:Calcium / Q000737:chemistry*; D002845:Chromatography; D004305:Dose-Response Relationship, Drug; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D046911:Macromolecular Substances / Q000737:chemistry*; D008956:Models, Chemical; D008962:Models, Theoretical; D010368:Pectins / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology; D013696:Temperature; D014783:Viscosity
chemical_list: D000577:Amides; D001672:Biocompatible Materials; D005782:Gels; D007477:Ions; D046911:Macromolecular Substances; D011108:Polymers; D011134:Polysaccharides; D010368:Pectins; D002118:Calcium