Wheat hemicelluloses

Development of Agriculture Left-Overs Fine Organic Chemicals from Wheat Hemicellulose-Derived Pentoses... 

Fig. 1 Simplified structure of wheat hemicelluloses (see Fig. 2 for FeA, GlcAp, a-Galp)...

Martel F, Estrine B, Plantier-Royon R, Hoffmann N, Portella C (2010) Development of Agriculture Left-Overs Fine Organic Chemicals from Wheat Hemicellulose- Derived Pentoses. In Top Curr Chem. doi 10 1007/128 2010 54... 

Nakahara W, Tokuzen R, Fukuoka F, Whistler RL (1967) Inhibition of mouse sarcoma 180 by a wheat hemicellulose B preparation. Nature 216 374-375... 

AGX are also the dominant hemicelluloses in the cell walls of hgnified supporting tissues of grasses and cereals. They were isolated from sisal, corncobs and the straw from various wheat species [4]. A more recent study on corncob xylans [30] showed the presence of a hnear, water-insoluble polymer... 

Potential resources of xylans are by-products produced in forestry and the pulp and paper industries (forest chips, wood meal and shavings), where GX and AGX comprise 25-35% of the biomass as well as annual crops (straw, stalks, husk, hulls, bran, etc.), which consist of 25-50% AX, AGX, GAX, and CHX [4]. New results were reported for xylans isolated from flax fiber [16,68], abaca fiber [69], wheat straw [70,71], sugar beet pulp [21,72], sugarcane bagasse [73], rice straw [74], wheat bran [35,75], and jute bast fiber [18]. Recently, about 39% hemicelluloses were extracted from vetiver grasses [76]. 

From recent literature it is known that the disintegration of lignified cell walls can be achieved by steam explosion treatments resulting in solubilization of partially depolymerized hemicelluloses [91,92]. The application of this method on wheat bran yielded feruloylated GAX with different feruUc acid content [93]. Partly depolymerized water-soluble, acetylated AGX was obtained from spruce wood by employing microwave treatment [94]. 

FTIR spectra of extracted wheat straw hemicellulose and cellulose do not exhibit this band (spectra not shown). From this point, the extracted wheat straw XRPP is also assigned to pectic substances. The intensity ratio of the bands i>as(COO ) at 1608 cm" and j (C 0) ester at 1740 cm corresponds to fully deesterified pectin and Me pectate... 

Few further measurements have been reported. The essentially unbranched structure of a xylan from wheat straw232 and of hemicellulose-A233... 

Aqueous alkaline extraction of wood was employed by Poumarede and Figuier48 in 1846 for the removal of a substance called wood gum. Similar very crude xylan or hemicellulose preparations were made by other workers of the early period. Extractions were made not only from wood sawdust, but from annual plant materials such as wheat straw, corn cob, etc.49-66... 

Water-holding capacity of hemicelluloses (contained in wheat brans and psyllium fiber) and celluloses may decrease mouth to rectum transit time, increase fecal weight, and decrease intraluminal pressure (36). These characteristics might be expected to interfere with calcium absorption decreasing time allowed for intestinal absorption, by diluting the concentration of calcium and... 

Fourth lesson - combination of different compounds in unique macrostructure provides unique performance properties. Starch is used extensively in nature to store carbon and energy. Starch is readily digested and must be protected from degradation by a resistant coating, for example, a seed (e.g. com, wheat or rice) or a skin (e.g. potato). Woody materials such as trees, soft plants and grasses are composed of a complex combination of aliphatic and aromatic compounds (cellulose, hemicellulose and lignin). 

The FP cellulose per unit (ml) volume and enzyme yield per unit (g) cellulose or substrate obtained on wheat straw, wood, and CTMP in SSF were higher than those obtained in LSF on wheat straw and wood (Tables I, II, and III). And wheat straw proved to be a better substrate than wood for cellulose production in SSF. This could be attributed to the polysaccharides (cellulose and hemicelluloses) of wheat straw being more readily available for the organism s growth and cellulose synthesis than those of wood. The hemicelluloses and cellulose were presumably not as available in wood, because of its high lignin content and high cellulose crystallinity, as in wheat straw. 

Unfortunately, pure xylan is an expensive carbon source for commercial-scale xylanase production. Therefore, several groups have tried to develop xylanase production on cheaper xylan-rich materials. The best candidates for the purpose appear to be water-soluble hemicellulose from steam-treated wood (63,69) and residues of annual plants like wheat bran (70). 

When the hyper-cellulolytic mutant T. reesei QM9414 was grown on various substrates derived from wheat straw in stirred batch culture, the highest specific growth rates were on holocellulose and the hemicellulose-A defined by O Dwyer (8) it grew poorly on lignocellulose. By contrast,... 

Table I. Growth of Trichoderma reesei QM9414 (Tr) and T. harzianum IMI275950 (Th) on wheat straw lignocellulose (lignocell.) or derived cellulosic materials from straw (cell., cellulose hemicell-A, hemicellulose-A holocell., holocellulose)...

However, oral administration of these polysaccharides had no effect. Hemi-celluloses from different higher plants caused regression of solid Sarkoma 180 in mice but not of ascites tumor. Arabinoglucuronoxylan isolated from wheat-straw hemicellulose was completely devoid of activity, whereas arabinoglucoxylan was highly active (Nakahara 31)). 

Enzymes should be added to the feed together with the pre-mix. Granulated enzyme products may readily be mixed with feed components, as they are based on normal feed components such as wheat or soy grits. A wide range of enzyme products are available. Enzyme products should contain specific enzyme activities necessary to degrade specific substances such as glucans, starch, protein, pectin-like polysaccharides, phytic acid, raffinose, stachyose, hemicellulose, and cellulose. 

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