• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.4
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• pp.64-70
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• 2010

In this study, hemicelluloses were pre-extracted from mixed hardwood chips using sodium hydroxide solution and then they were isolated from pre-extractives by using various solvents. Isolation was conducted by precipitating hemicelluloses with isopropanol, ethanol, 1,4-dioxane, dimethylsulfoxide (DMSO) and potassium hydroxide (KOH), respectively. The precipitate yield on alkali pre-extractives was the highest when hemicelluloses were isolated by DMSO and then precipitated with ethanol. Most precipitates were yellow colored. The efficiency of isolation was evaluated by analysing the characteristics of isolated hemicelluloses. Isolation using DMSO, KOH and 1,4-dioxane ($80^{\circ}C$) showed rather high efficiency. The highest total separation efficiency was about 77% when alkali pre-extractives were reacted with KOH and precipitated with ethanol. The quantity and purity of isolated hemicelluloses were affected by the solvent type.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.5
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• pp.60-67
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• 2011

Hemicelluloses pre-extracted from Korean mixed wood chip were investigated as a wet-end additive. Hemicelluloses dissolved in hot water and alkali solution were isolated by ethyl alcohol precipitation from pre-extractives. They showed molecular weight of 9,000 ~ 27,000 g/mol as revealed by size exclusion chromatography. The reduction of molecular weight through hot water extraction was caused by autohydrolysis. Chemical composition of the hemicelluloses were analyzed with high-performance liquid chromatography and UV-Vis spectroscopy. As the surface charge of isolated hemicelluloses were negative, the adsorption of hemicelluloses onto softwood unbleached kraft pulp fiber was promoted by poly-DADMAC. The physical properties of handsheets increased as the molecular weight of hemicellulose increased. On the other hands, the optical property decreased with hemicellulose adsorption.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.83-91
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• 2011

Hemicelluloses are useful materials for papermaking and other biotechnological applications. To recover and further utilize the hemicelluloses, this study carried out the pre-extraction of the hemicelluloses from Korean mixed hardwoods chips using hot water and sodium hydroxide solution at various temperature and time conditions. Through the hot water pre-extraction, the wood components of 22% was extracted and the 35% of the hemicelluloses which were contained in the original wood chips were dissolved into the pre-extractives. The yield of the pre-extractives was more significantly influenced by the pre-extraction temperature than the time. The pre-extractives with the yield of 30% could be obtained by alkali pre-extraction and alkali concentration was the most important factor. It had lower hemicellulose content but high molecular weight, compared with the hot water pre-extractives.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.257-260
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• 2003

Hemicelluloses, one of the most abundant natural polysaccharides, are comprised roughly in one-fourth to one-third of most plant materials. Hemicelluloses contain mixtures of 50-200 five-carbon sugars(xylose and arabinose) and six-carbon sugars(glucose, galactose, mannose, and rhamnose), plus lesser amounts of the sugar acids(glucuronic acid and galacturonic acid). The kinds of hemicelluloses are A, B, and C. The interesting substance of them is hemicellulose B. However, the prodution level of hemicellulose B is very low. Thus, this study was concentrated on increasing the recovery yield of hemicellulose B from rice bran.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.241-251
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• 1981

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.21-28
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• 2004

Com stalk was evaluated to verify the potential as a raw material for papermaking. The lower lignin content and higher hemicelluloses content of cornstalk than any woods were considered to be beneficial for pulping and strength properties of paper. The average fiber length of com stalk was similar to those of hardwood, but longer fiber fraction is little bit included. It was found that the refining of pulp can be eliminated because of higher hemicelluloses content and narrower fiber characteristic. Disadvantages of cornstalk pulp were lower bulk and opacity, but it can be overcome by the proper use of wood pulp and filler.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.121-122
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• 2006

Paralleled with the development of new materials we need to develop methods and techniques to reveal the environmental interaction and impact of the new materials. Small changes in the chemical structure or product formulation may render the product less environmentally adaptable. Degradation products formed from PLLA were identified after aging in different environments and their assimilation in the biotic environment was shown. Green and degradable hydrogels could be designed from renewable hemicelluloses and lactic acid. Hemicelluloses are a renewable and highly interesting raw material source for new green polymers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.10a
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• pp.266-272
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• 2008

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.20-25
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• 1996

Wood chips of oak(Quercus mongolica) and larch(Larix leptolepis) were exploded with the optimum condition. Main components of exploded wood were separated with hot hot water and methanol. The hemicelluloses were purified from hot water extracts and alditol complexs were prepared from purified hemicellulose. And also, cellulose nitrate was prepared from extractive residue and characterized. The results can be summarized as follows. 1. Amounts of carbohydrate(72~79%) in the crude hemicellulose of larch wood was more than those of oak wood(55~66%). 2. The crude hemicelluloses were mainly composed of oligosaccharides in oak wood but those in larch wood contained about 50% monosaccharides. 3. Decolorization of hemicellulose was successful with activated charcoal and ion-exchange resin treatment. The alditol yields were 56.3~82.9%. 4. The degree of substitution(D.S.) of cellulose nitrate was 1.95~2.87 and it showed a good acetone solubility.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.345-356
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• 2012

We investigated the changes of fruit quality parameters, polysaccharide contents and cell wall components during maturation and ripening of two Korean pear cultivar 'Hanareum' and 'Manpungbae' compared with 'Niitaka' pear (Pyrus pyrifolia Nakai) which showed different physiological maturity based on days after full bloom (DAFB). Flesh firmness decreased continuously with fruit development and maturation, reaching a final level of 29.4, 33.5, and 27.4N at maturity in 'Hanareum' (127 DAFB), 'Manpungbae' (163 DAFB), and 'Niitaka' (170 DAFB), respectively. The level of ethylene production was very low in early season 'Hanareum' pear which showed at most 0.39 ${\mu}L{\cdot}L^{-1}$ at maturity and no ethylene was detected in 'Manpungbae' and 'Niitaka' at maturity. Fructose was the most abundant soluble sugar during fruit maturation in the pears tested and an increase of sucrose was observed during fruit ripening in the Asian pears commonly. Ethanol insoluble solids (EIS) content decreased gradually with different levels among the pear cultivars as fruit ripens consisted of 10.79, 12.72, and 12.75 $mg{\cdot}g^{-1}$ FW. The amount of total soluble polyuronides was higher in early season cultivars 'Hanareum' than those of mid-season cultivar 'Manpungbae' and 'Niitaka'. In 'Niitaka' which harvested most late season, the level of 4% KOH soluble hemicelluloses was lower than 'Hanareum' and 'Manpungbae' and maintained constantly during fruit ripening period. Cellulosic residues were determined high level in 'Niitaka' which showed 612.33 ${\mu}g{\cdot}mg^{-1}$ EIS at maturity when compared with 'Hanareum' (408.0 ${\mu}g{\cdot}mg^{-1}$ EIS) and 'Manpungbae' (538.67 ${\mu}g{\cdot}mg^{-1}$ EIS). The main constituents of cell wall neutral sugars which consisted of arabinose, xylose, galactose, and glucose were decreased gradually with onset of fruit ripening regardless of cultivar. Arabinose which was predominant in 'Hanareum' pear decreased at the last stage of ripening, but the changes of cell wall neutral sugar during ripening were not occurred in 'Niitaka' pear. The change of molecular mass distribution in water soluble pectin observed dominantly at the early stage of fruit development. Depolymerization of 4% KOH-soluble hemicelluloses and degradation of xyloglucan showed in early-season cultivar 'Hanareum' during fruit maturation, and degradation of those fractions were detected only at the early stage fruit development in mid-season cultivar 'Manpungbae' and 'Niitaka'. The molecular mass profile of CDTA soluble pectin, $Na_2CO_3$-SP and 24% KOH soluble hemicelluloses showed no significant change during fruit maturation regardless of cultivar.