Fractionation and characterization of polysaccharides from abaca fibre

• Published in: Carbohydrate polymers 1998, Vol.37 (4), p.351-359
• Main Authors: Sun, RunCang, M. Fang, J., Goodwin, A., M. Lawther, J., J. Bolton, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; chemical composition; Chemical constitution; dietary fiber; Exact sciences and technology; fractionation; Fundamental and applied biological sciences. Psychology; Hemicellulose–lignin complex; Lignin; Molecular weight; Musa textilis; Natural polymers; phenolic compounds; physicochemical properties; Physicochemistry of polymers; Plant physiology and development; Polysaccharides; Starch and polysaccharides; Sugars; uronic acids
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/S0144-8617(98)00046-0

Abaca fibre polysaccharides were fractionated into water soluble, pectic, 1% NaOH soluble, hemicellulosic and cellulose fractions by extraction with hot water, dilute hydrochloric acid (pH 1.6), aqueous 1% NaOH and 17.5% NaOH, respectively. Cellulose (60.4–63.6%) and hemicelluloses (20.8%) were the major polysaccharides in abaca fibres. The hot water soluble polysaccharides contained noticeable amounts of pectic substances and a large proportion of neutral polysaccharides. The pectic polysaccharide preparation was enriched in both galacturonic acid and neutral sugars, including xylose, glucose, galactose, arabinose, and rhamnose. Extraction of the fibre with aqueous 1% NaOH produced the hemicellulose–lignin complex, which was enriched in xylose and, to a lesser extent, glucose-, arabinose- and galactose-containing polysaccharides, together with 7.6% associated lignin. Further extraction of the delignified fibre residue with aqueous 17.5%. NaOH removed the hemicellulose fractions, which were strongly enriched in xylose-containing polysaccharides. Besides ferulic and p-coumaric acids, six other phenolic monomers were also detected in the mixtures of alkaline nitrobenzene oxidation of associated lignin in all the polysaccharide fractions. The content of bound lignin in water soluble, pectic, and 1% NaOH soluble polysaccharides (Fractions 1, 2, and 3), isolated directly from the lignified fibres, was 12 times that of the hemicellulosic preparations (Fractions 4 and 5) isolated from the delignified fibre residues.