title: Material properties of concentrated pectin networks.
abstract: We have examined the mechanical behaviour of different types of pectin at high concentrations (> 30% w/w), relevant to the behaviour of pectin in the plant cell wall, and as a film-forming agent. Mechanical properties were examined as a function of counterion type (K(+), Ca(2+), Mg(2+)), concentration and extent of hydration. Hydration was controlled in an osmotic stress experiment where pectin films were exposed to concentrated polyethylene glycol [PEG] solutions of known osmotic pressure. We investigated the mechanical behaviour under simple extension. The results show that the swelling and stiffness of the films are strongly dependent on pectin source and ionic environment. At a fixed osmotic stress, both Ca(2+) or Mg(2+) counterions reduce swelling and increase the stiffness of the film.
authors.affiliation: Division of Food Materials Science, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
authors.forename: Gabor
authors.initials: G
authors.lastname: Zsivanovits
authors.forename: Alistair J
authors.initials: AJ
authors.lastname: MacDougall
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Smith
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Ring
mesh_terms: D002412:Cations / Q000737:chemistry; D002473:Cell Wall / Q000737:chemistry; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D010368:Pectins / Q000737:chemistry*; D010944:Plants / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D002412:Cations; D011092:Polyethylene Glycols; D010368:Pectins