Larch wood

The enzymic digestion of an adenosine diphosphate sugar fraction from larch wood leads, among other monosaccharide products, to a fructose.20 This result suggests the occurrence of a corresponding fructosyl ester, but its structure remains undetermined. 

Oligosaccharide derivatives of uridine 5 -pyrophosphate are probably present in higher plants. Cellobiose and a disaccharide composed of a glucose and an arabinose were identified among products of enzymic hydrolysis of a uridine diphosphate sugar fraction from larch wood.20... 

Arabo-galactan from larch wood Sedimentation and Diffusion 16,000 A highly branched molecule 62... 

PROP Derived from water extraction of Western larch wood having galactose units and arabinose units in the ratio of approx. 6 1. Mp >200° (decomp). Sol in water. 

Wood Solubility. The solubility of wood in various solvents is a measure of the extraneous components content. No single solvent is able to remove all of the extraneous materials. Ether is relatively nonpolar and extracts fats, resins, oils, sterols, and terpenes. Ethanol/ benzene is more polar and extracts most of the ether-solubles plus most of the organic materials insoluble in water. Hot water extracts some inorganic salts and low molecular weight polysaccharides including gums and starches. Water also removes certain hemicelluloses such as the arabinogalactan gum present in larch wood see Table I). 

Larch wood Larix occidentalis) Decomposed Douglas-fir Pseudotsuga menzeisii) Ponderosa pine Pinus ponderosa) Aspen... 

Some hemicelluloses have practical applications such as larch arabinogalactan, which is a water-soluble gum found in the heartwood of trees from Larix genus, and which is used in processed food as an emulsifier, or in pudding mixes, etc. A Py-GC/MS study of arabinogalactan from larch wood indicated the presence of the galactose unit and of arabinose unit in the ratio 6 1, as it is known in this material. The arabinose units were identified mainly by the formation of 1,4-anhydro-L-arabinopyranose, which elutes faster than the corresponding hexoses. The structure shown below was therefore confirmed by Py-GC/MS [64]. 

The methods used for structural analysis of (4-0-methylglucurono)xylans have also been applied to the arabinogalactans from larch wood. They include methylation, partial hydrolysis, and Smith degradation. In addition, Barry degradation has found extensive use. Because of the few, detailed, structural investigations so far reported, and because of the complicated nature of the polysaccharides, each of the four species studied will be discussed separately. 

Methyl Sugars Obtained on Hydrolysis of 0-Methylated Arabinogalacians from Larch Wood... 

Jennison (29) has shown that thiamin is required for growth of many wood-destroying fungi. Kennedy (30) has shown that the arabino-galac-tan of larch wood provides a substrate which the fungi use in becoming initially established within this wood. 

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