Lignin complexes

Arabinan. This highly soluble polymer is found in the extracts of many fmits and seeds, in the boiling water extracts of pine wood (127), in the extracts of marshmallow roots (A/t/jaea officina/is) (128), and aspen (63) and willow (Sa/ix a/ba F) (129) bark. Because arabinan can be isolated from mildly degraded pectin fractions, it is often difficult to determine whether it is a hemiceUulose or a labile fragment of a larger polysaccharide and/or lignin complex. Arabinans have a complex stmcture composed almost entirely of 5-linked a-L-arabinofuranosyl units with similar residues linked to them at C-2 and/or C-3 and is soluble in 70% aqueous methanol solution. 

Detergent Methods. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) methods (2), later modified for human foods (13), measure total insoluble plant cell wall material (NDF) and the cellulose—lignin complex (ADF). The easily solubilized pectins and some associated polysaccharides, galactomaimans of legume seeds, various plant gums, and seaweed polysaccharides are extracted away from the NDF. They caimot be recovered easily from the extract, and therefore the soluble fiber fraction is lost. 

The 1430 cm.-1 band establishes the presence of aliphatic groupings in the-lignin complex. A difference in relative intensity at 1325 cm.-1 should also be pointed out. Such variations are more evident at 1265, 1255 and 1220 cm.-1, which are in the spectral region of aromatic or aliphatic unsaturated C—0 groups, and also at 1140, 1.163, 1155 and 1125 cm.-1. These differences possibly are due to different atomic... 

Dissociation of the Protein-Poly phenolic Complex and Characterization of the Polyphenolic Fraction. Since Indulin ATR is almost completely soluble in THF while the APPL s are quite insoluble in this solvent, but are soluble in DMF, a sequence of different percentage mixtures of these two solvents was used in order to dissociate the protein-lignin complexes for further analyses of the lignin part. 

Consequently any model proposed to account for the dissociation of individual components from associated kraft lignin complexes should pay particular attention to restrictions that would rationalize the concomitant first... 

Lignin complex -m whiskey barrels pEVERAGE SPIRITS DISTILLED] (Vol 4)... 

Cu / lignin complexes physically adsorbed on wood constituents Cu / cellulose complexes... 

HCr04 —> HCr04 / lignin complexes Fig. I Scheme of the interaction of CCA with wood. 

CrAs04-lignin complexes Inorganic CrAs04 precipitates on cellulose... 

Cu -lignin complexes Physically adsorbed on wood constituents... 

The products formed when CCA is reacted with wood are composed mainly of the CuCr04-lignin complexes, CrAs04-lignin complexes, and CrAs04 precipitates on cellulose. However, the actual proportions of various chemical species are dependent on the relative proportions of Cu, Cr, and As present in the formulation (40). 

These enzymes attack preferably the frame substances of a single plant cell or the plant association in the plant tissue. The framing substances consist of polysaccharides, especially cellulose (6-1,4-glycoside) and in-built pectines (esters of a-l,4-polygalacturonic acid) partially also lignin (complex polymers of coniferylic alcohol) which, however, cannot be cleaved by carbohydrases. 

Retted fibers such as jute and kenaf have three principal chemical constituents, namely, a-cellulose, hemicelluloses, and lignin. The lignin can be almost completely removed by chlorination methods in which a soluble chloro-lignin complex is formed, and the hemicelluloses are then dissolved out of the remaining holocellulose by treatment with dilute alkali. The final insoluble residue is the a-cellulose constituent, which invariably contains traces of sugar residues other than glucose. 

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