[Distribution of free carboxyl groups in native pectins from fruits and vegetables].
Pectins from 18 kinds of fruit and vegetable are extracted with ammonium oxalate from the alcohol-insoluble substance and fractioned on DEAE-Sephacell. All the fruit pectins as well as tomato and sunflower pectin have in their distribution of the esterification degree a concentration maximum in the highly esterified range, that is above an esterification degree of 60%. With lower esterification degrees the concentration decreased continuously. Vegetable pectins from cucumbers, celery, and tomato-paprika (sweet, red) have their maximum within an esterification range of 50-60%. The carboxyl groups are randomly distributed in all these preparations. As against that, vegetable pectins from red and white cabbage, cauliflower, large radish and carrots have in addition to a pectin fraction with randomly distributed carboxyl groups another one, pectin molecules of which have blocks of free carboxyl groups. The latter fraction may constitute up to 50% of the pectin.
D002848:Chromatography, DEAE-Cellulose; D004952:Esters / Q000032:analysis; D005638:Fruit / Q000032:analysis*; D010368:Pectins / Q000032:analysis*; D014675:Vegetables / Q000032:analysis*
D004952:Esters; D010368:Pectins
Verteilung der freien Carboxylgruppen in nativen Pektinen aus Obst und Gemüse.