Spruce, polysaccharides from

Willfor, S. and Holmbom, B. (2004) Isolation and characterization of water-soluble polysaccharides from Norway spruce and Scots pine. J. Wood Sci. Technol, 38, 173-179. 

During the past decade, MALDI-TOF MS has proven to be an effective tool for the analysis of oligo- and polymeric mannoglucans (for extensive reviews see [222,223]). SEC/MALDI mass spectrometry was employed in the analysis of hemicelluloses isolated by microwave heat-fractionation from spruce and aspen wood [94]. These methods allowed the separation and characterization of the oligo- and polysaccharide fractions derived from the xylan and mannan components of both woods [224]. 

For the study of soluble polysaccharides, a treatment with diluted TFA is sufficient and the reaction time can be kept short (7). Soluble polysaccharides of wood are separated from holocellulose by extraction with alkali. Wise et al. (10) term the extract with 5% KOH polyoses (hemicelluloses) A. Polyoses A can be hydrolyzed completely with 2N TFA within 1 hr. The chromatograms of the hydrolysates of polyoses A from spruce and beech holocelluloses recorded with a sugar analyzer (Biotronik ZA 5100) are shown in Figure 1. 

The whole procedure normally takes about 1 hr. The acid is then evaporated, and the dry matter can be analyzed. This method can be applied to cellulose from wood, as a-cellulose or pulp, or to other celluloses (e.g., cotton) as well as to cellulosic materials with higher amounts of other polysaccharides (e.g., holocellulose). The chromatograms of the hydrolysates of a-cellulose from beechwood and of holocellulose from sprucewood (Figure 6) are examples of the application of this method. Compared with sulfuric acid hydrolysis, the total sugar yield from the spruce holocellulose is higher after the hydrolysis with concentrated TFA (Table II). Regarding the individual sugars, it can be seen that the... 

A problem but little discussed in the hterature is the possible association of polysaccharide molecules of various kinds with noncarbohydrate molecules. The association can be random, and a direct fractionation would then be impossible. Thus, it has frequently been observed in the authors laboratory that hemicelluloses containing lignin could not be separated into the pure components, but, after further dehgnification, they could be readily fractionated. It is possible that similar comphcations may also occur with other types of polysaccharide, for example, protein- or lipide-polysac-charide complexes. In this connection, it should be noted that the solution obtained on dehgnification of some materials may contain polysaccharide material of particular interest. For instance, the main part of the galactan present in spruce compression wood can be recovered from such a solution. ... 

Polysaccharides of the xyloglucan may be of relatively widespread occurrence, and examples have been reported from the bark of Engel-mann spruce (Picea engelmann), 5 red-spruce compression-wood,155 the seeds of white mustard (Brassica alba),156 and sycamore callus-cells.157 The mustard156 and sycamore157 polysaccharides are charac-... 

Occurrence. There are many polysaccharides that yield D-mannose on hydrolysis. For preparative purposes, the most important source is the seed of the tagua palm Phytelephas macrocarpa, also known as vegetable ivory.117 Salep mucilage from tubers of Orchidaceae, the seed of Phoenix canariensis, and white spruce hemicellulose are rich enough sources of D-mannose that they have been used for the preparation of this sugar. Konjac flour, which is commonly available in Japan from Amorphophallus konjac, provides another source of this hexose.118... 

As mentioned previously (see Part I, p. 255), only minor quantities of hemicelluloses can be removed from softwood by direct extraction with alkali. Very likely, the hemicelluloses are protected by the lignin, especially by that portion which surrounds the polysaccharides in the secondary wall. Isolation of softwood xylans by direct, alkaline extraction of tbe wood seems to have been used on only two occasions. Saarnio, using wood shavings of Norway spruce Picea abies), was able to obtain a relatively pure arabino-(4-0-methylglucurono)xylan in a yield of 3%, simply by extracting with 5% aqueous potassium hydroxide, a remarkable result. With wood of loblolly pine, Jones and Painter obtained a mixture of hemicelluloses, in a yield of about 1%, on direct extraction with 25% aqueous potassium hydroxide solution containing 4% of borate. 

Following previous attempts to isolate a pure mannan from wood, Hess and Liidtke reported the isolation of such a polymer from a spruce sulfite pulp. Husemann, much later, obtained a similar product from a spruce holocellulose. It is now clear that these polysaccharides could not possibly have been mannans. Wise and Ratliff found that over half of the D-mannose residues in black spruce wood are intimately associated with the a-cellulose portion, perhaps as an integral part of the cellulose. A skinlike substance, insoluble in cuprammonia, was isolated by Rollin-... 

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