The chemistry of Pinus radiata . VI. The water-soluble galactoglucomannan

The two major components of the water-soluble polysaccharides extracted from the sapwood of Pinus radiata were a galactoglucomannan and an arabinogalactan. The galactoglucomannan had a number average degree of polymerization of approximately 30, and on complete acid hydrolysis it yielded D-mannose, D-galactose and D-glucose in the ratio 4.5 : 1.3 : 1.0. The structural determination of this polysaccharide by methylation analysis and 13C n.m.r. suggested that it is a linear glucomannan with a-D-galactopyranosyl residues as single side units. No evidence could be found of any branches in the polymer, although the possibility of a small degree of branching cannot be dismissed.