Characterization of hemicellulose

Tejero. Olive polysaccharides. IX. Characterization of hemicellulose B OE092 from the pulp of Hojiblanca variety of olive. An Quim Ser C 1987 83(1) ... 

Sun, X. F., et al. "Fractional Isolation and Physico-chemical Characterization of Hemicelluloses by a Two-Stage Treatment." Journal of Agricultural and Food Chemistry 50 (2002), 6400-6407. 

Characterization of Hemicelluloses from Wood Employing Matrix-Assisted Laser Desorption/lonization Time-of-Flight Mass Spectrometry... 

Chen, W. H., Kuo, P. C. Torrefaction and co-torrefaction characterization of hemicellulose, cellulose and lignin as well as torrefaction of some basic constituents in biomass. Energy 2011b, 36, 803-811. 

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]. 

The number of reports about hemicelluloses that have been covered by this review indicates the significantly increased importance of all types of hemicelluloses as plant constituents and isolated polymers during the last decade. Attention has been paid not only to known hemicelluloses but also to the primary structure, physicochemical, physical, and various functional properties of hemicelluloses isolated from hitherto uninvestigated plants. The efforts to exploit a variety of plant as potential sources of hemicelluloses were pointed out particularly for agricultural crops, wood wastes, as well as for by-products of pulp and rayon fiber technologies. Many studies were devoted to characterize seed-storage hemicelluloses from plants that have been traditionally applied in food and medicine of many underdeveloped countries to find substitutes for imported commercial food giuns. 

We have seen that lignin is a highly branched amorphous pol3rmer containing an extremely complex array of structures and that when in situ in the wood, it is a graft polymer with cellulose and hemicellulose to boot. Characterization of lignins thus becomes a problem. 

The estimation of total hemicellulose, without characterization of individual sugars, may be achieved by subtracting the ADF value from the NDF value obtained from duplicate samples of the same weight. There are, however, four main possible interferences with this procedure. 

The reliability of any attempt at determination or characterization of lignin by NMR is dependent on fortuitous similarities in the various spin relaxation parameters. For example, values of T2(H) for lignins tend to be longer than those for cellulose or hemicellulose (Newman 1987, Tekely and Vignon 1987), but the differences are too small to be important for typical values of tp. Values of TI/((H) are sometimes indistinguishable for various components of a sample, and even when differences have been observed, the values are so long that the differences would have little effect on the results (Gerasimowicz et al. 1984, Haw et al. 1984, Maciel et al. 1985). 

Characterization of the low molecular weight carboxylic acids was successfully achieved following benzylation technique developed in our laboratory (Pakdel, H. Roy, C. Biomass, in press). Formic and acetic acids as decomposition products of cellulose and hemicellulose were the major constituents of pyrolysis oils (15). 

Chaa, L. Joly, N. Lequart, V. Faugeron, C. Mollet, J. Martin, P. Morvan, H. Isolation, characterization and valorization of hemicelluloses from Aristida pungens leaves as biomaterial. Carbohydr. Polym. 

The method of characterization by high-performance liquid chromatography [HPLC] is as follows 25 mg of hemicellulose was put into 50 mL volumetric flask and pure water was added to the mark. The mixture was shaken and then filtered [first few milliliters of filtrate was discarded]. The solution was then filtered through a membrane filter of 0.2 pm cellulose nitrate. Then about 100 mL solution was injected into the HPLC system via a loop injector with a 20 mL, using an isocratic elution system with distilled water with a mobile phase, flow rate 0.8 mL/min. The detection was made using a UV detector at a wavelength of 280 nm [34]. 

Characterization of Corn Cobs Hemicellulose Using Infrared Spectrophotometry... 

Figure 8.3a Characterization of the infrared vibration of corn cobs hemicellulose and cadmium complex.

Gabrielii, I., Gatenholm, P., Glasser, W.G., Jain, R.K., Kenne, L. Separation, characterization and hydrogel-formation of hemicellulose from aspen wood. Carbohydr. Polym. 43, 367-374 (2000)... 

---