Chemically methylated and reduced pectins: preparation, characterisation by 1H NMR spectroscopy, enzymatic degradation, and gelling properties
| Autor: | Inge Lundt, Christoph Rosenbohm, Tove M.I.E. Christensen, Niall W. G. Young |
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| Rok vydání: | 2003 |
| Předmět: |
Magnetic Resonance Spectroscopy
Time Factors animal structures food.ingredient Chemical Phenomena Pectin macromolecular substances Methylation complex mixtures Biochemistry Mass Spectrometry Substrate Specificity Analytical Chemistry food Organic chemistry Citrus Pectin Pectinase Pectin lyase chemistry.chemical_classification Chromatography biology Chemistry Physical digestive oral and skin physiology Organic Chemistry Aspergillus niger Temperature food and beverages General Medicine biology.organism_classification Biodegradation Environmental Polygalacturonase Enzyme chemistry Proton NMR Pectins Rheology Gels Saponification |
| Zdroj: | Carbohydrate Research. 338:637-649 |
| ISSN: | 0008-6215 |
| Popis: | The gelling properties of pectins are known to be closely related to the degree of methylation (DM) and the distribution of the ester groups. In order to investigate this dependency, a natural citrus pectin (DM 64%) has been methylated to pectins with higher DM or saponified to achieve pectins with lower DM. A simple method for determination of DM by 1 H NMR spectroscopy is presented. New modified pectins have been prepared by treatment of pectins having different DM with NaBH 4 to reduce selectively the methyl esters to primary alcohols in the presence of free acids. The degree of reduction (DR) and the DM of the remaining carboxylic acids could likewise be determined by 1 H NMR spectroscopy. The new reduced pectins are recognized by the pectin degrading enzymes polygalacturonase PGI and PGII as well as by pectin lyase, all from Aspergillus niger , but the enzymes exhibit lower specific activities as compared with unmodified pectin. The new reduced pectins exhibit high gelling properties. |
| Databáze: | OpenAIRE |
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