Pectic acids
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Pectic acids , also polygalacturonic acids , are pectins with a degree of esterification below 5%. The pectic acids belong to the group of polymeric carboxylic acids . They are insoluble in water, transparent and gelatinous and occur in overripe fruits and some vegetables. In plants, in the presence of calcium and magnesium ions, pectic acids form an insoluble, high molecular weight complex called protopectin , the structure of which is little known.
Pectic acids are a product of pectin degradation and are formed from pectin through demethylation . The gelling properties correspond to those of low methylated pectins. At a high pH value and high concentration of multivalent cations , the salts of pectic acid, the pectates, precipitate.
Individual evidence
- ^ Peter Nuhn : Naturstoffchemie , S. Hirzel Wissenschaftliche Verlagsgesellschaft, Stuttgart, 2nd edition, 1990, ISBN 3-7776-0473-9 , p. 218.
- ↑ a b Otto Albrecht Neumüller (Editor): Römpp Chemie Lexikon , 8th edition, Frank'sche publishing firm, Stuttgart 1983, ISBN 3-440-04513-7 , p 3,022th