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Uronic acid composition

Rha, Ara and Gal are the neutral sugar components from all the fractions. Xyl is not present in Fla and is significantly present in the hemicellulose fractions, indicating that this monosaccharide is component of hemicellulosic polymers. Chemical composition of the water fractions were determined (Table V). High protein contents and the presence of O-acetyl-groups were observed in four aqueous fractions. Neutral sugar and uronic acid composition points to inclusion of these polymers in the class of pectic polysaccharides. [Pg.558]

A. Haug and B. Larsen, Quantitative determination of the uronic acid composition of alginates, Acta. Chem. Scand., 16 (1962) 1908-1918. [Pg.287]

Sanchez-Machado, D. I., Lopez-Cervantes, I, Lopez-Hernandez, J., Paseiro-Losada, P., and Simal-Lozano, J. (2004), Determination of the uronic acid composition of seaweed dietary fibre by HPLC, Biomed. Chromatogr., 18(2), 90-97. [Pg.553]

Uronic Acid Composition and Block Length. A sample containing 75 mg alginic acid was first suspended in a small volume of D2O, then fully neutralized by titration with 1.0 M NaOD. D2O was added to achieve a final concentration of 25 mg alginic acid/mL D2O. Equilibration of at least one hour was allowed prior to NMR acquisition. The uronic acid composition was determined by NN spectroscopy, with a 2 s pulse repetition time and 16,000 scans. The reported composition and block lengths were the average of two determinations. [Pg.246]

Smidsrpd, O., Hang, A., 1968. Dependence upon uronic acid composition of some ion.exchange properties of Alginates. Acta Chem. Scand. 22(6), 1989-1997. [Pg.512]

Uronic acid compositions is determined colorimetrically using the m-hydroxydiphenyl assay described by Bramenkrantz and Asboe-Hansen (1973). [Pg.139]

Recently, the alkah-soluble hemicelluloses of hardwood dissolving pulps have been investigated [28]. Their composition and molecular properties depended on the pulp origin and steeping conditions. The MGX of the j8-fraction from press lye had a low uronic acid content (ratio of MeGlcA to Xyl is about 1 20). The molecular weight of the hemicellulose fractions varied between 5000 and lOOOOg/mol. [Pg.8]

Table II. Carbohydrate compositions (weight percentage) of individual oligomer peaks purified (QAE-Sephadex or HPLC ion-exchange separation, respectively) from mixtures of citrus pectin oligomers or B fruit extracts Compositions shown are for peaks whose biological activity is described in Figure 4. Uronic acid values are based on colorimetric assay. Proportions of neutral sugars were determined by GC and adjusted so that totals equal 100%. In fact, some oligomers (G7 peaks 8, 9 and 10. B extract peak 10) produced small (less than 1 % of the total integrated area), unknown peaks in the GC chromatograms. Table II. Carbohydrate compositions (weight percentage) of individual oligomer peaks purified (QAE-Sephadex or HPLC ion-exchange separation, respectively) from mixtures of citrus pectin oligomers or B fruit extracts Compositions shown are for peaks whose biological activity is described in Figure 4. Uronic acid values are based on colorimetric assay. Proportions of neutral sugars were determined by GC and adjusted so that totals equal 100%. In fact, some oligomers (G7 peaks 8, 9 and 10. B extract peak 10) produced small (less than 1 % of the total integrated area), unknown peaks in the GC chromatograms.
The determination of the sugar composition was performed with and without prehydrolysis to determine the cellulose content. Cellulose was present in soy meal and in WUS, the content was respectively 17.2 and 17.9 mol%. Both soy meal and WUS contained mainly galactose, glucose (cellulose), arabinose and uronic acids and their sugar compositions were very similar. This indicates that no sugar residues were specifically removed during the isolation procedure. [Pg.513]

ChSS and DASS were rich in arabinose, galactose and uronic acids. These were, as expected, pectin-rich extracts and had a very similar sugar composition. The 1 MASS fraction was also rich in arabinose, galactose and uronic acids, but next to that it is also enriched in... [Pg.513]

Methylation analyses of fractions N1 indicated that the linkage pattern of uronic acid residues (table 2) remains unchanged during ripening whereas the glycosidic linkage composition of neutral sugar residues showed different alterations. [Pg.654]

Glycosidic linkage composition of the uronic acid residues in fraction N1... [Pg.654]

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2- uronate

Uronates

Urones

Uronic

Uronic acid composition determination

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