ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Hemicelluloses from the young twigs of white willow (Salix alba). I. Isolation and characterization of the rough fractions of the wood hemicelluloses

P. Kováč and F. Rendoš

Institute of Chemistry, Slovak Academy of Sciences, Bratislava

Abstract:  In the presented paper the step-wise extraction of holocellulose of the young twigs from white willow (Salix alba L.), using different solvents for extraction is described. A hydrolysate of hemicelluloses, precipitable from an ammonia extract with ethanol contained D-xylose, D-galactose, D-glucose and L-arabinose in the molar ratio 60 :2 : 1 : 1. Hemicelluloses precipitable with ethanol from a holocellulose extract with 4.5 % NaOH, after hydrolysis afforded D-xylose, D-glucose, D-galactose, and L-arabinose in the molar ratio 190 : 11 : 2 : 1. A mannan-rich fraction of hemicelluloses was prepared by the holocellulose extraction with a solution containing 8 % NaOH and 4 % H₃BO₃ and subsequent precipitation with ethanol. The water-soluble part of this fraction contained D-xylose, D-mannose, D-glucose and D-galactose in the molar ratio 10 : 7 : 6 : 1. The molar ratio of the monosaccharides in the water-insoluble part of this fraction of hemicelluloses was Xyl: Glc: Man = 17 : 2 . 5 : 1. Hemicelluloses, extracted from holocellulose by 0.05 N-HCl yielded hydrolysate with the molar ratio of monosaccharides Glc : Gal: Ara : Xyl : Rha = 14.5 : 11  1 : 1 : 0.8.

Full paper in Portable Document Format: 2011a862.pdf (in Slovak)

Chemical Papers 20 (11) 862–869 (1966)