Hydration of pectic polysaccharides.
The hydration and swelling of pectic polysaccharides was examined at different pHs and ionic strengths as a function of osmotic stress. For weakly charged pectic polysaccharides at low concentrations of a monovalent salt (20 mM), the main driving force for swelling originates from a polyelectrolyte effect due to the translational entropy of ions within the film. Swelling is reduced at higher salt concentrations and lower pHs. Polyelectrolyte collapse and minimal swelling is observed for more highly charged pectic polysaccharides. Replacement of the Na(+) counterion with Ca(2+) results in minimal swelling and the formation of network structures even for the weakly charged pectic polysaccharides.
Ryden
P
P
Food Biopolymer Section, Institute of Food Research, Norwich Laboratory, Norwich Research Park, Colney, Norwich NR4 7UA, UK. Peter.Ryden@bbsrc.ac.uk
MacDougall
A J
AJ
Tibbits
C W
CW
Ring
S G
SG
D000042:Absorption; D002122:Calcium Chloride / Q000494:pharmacology; D002236:Carbohydrate Conformation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005685:Galactans / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013816:Thermodynamics; D014867:Water / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology
D005685:Galactans; D010936:Plant Extracts; D014867:Water; D012965:Sodium Chloride; D010368:Pectins; D002122:Calcium Chloride