title: Structure and thermal property of alkaline hemicelluloses from steam exploded Phyllostachys pubescens.
abstract: An environmentally friendly pretreatment process was developed to fractionate hemicelluloses from dried and water-immersed Phyllostachys pubescens chips by steam explosion followed with alkali and alkali/ethanol extractions. The detailed chemical and structural features of the isolated hemicellulosic fractions were comparatively investigated by HPAEC, GPC, FT-IR, (13)C NMR spectroscopies, and TGA analysis. It was found that the xylose/arabinose ratios of hemicelluloses obtained from alkali and alkali/ethanol extractions were 21.5-34.4 and 7.7-9.9, respectively, suggesting that hemicelluloses extracted with alkali had relatively lower degree of branches than those extracted with alkali/ethanol. Hemicellulosic fractions isolated from the water-immersed samples were obtained in high yields and exhibited similar compositions, which can be used as raw materials for production of value-added products. Furthermore, the hemicelluloses extracted with alkali had relatively higher molecular weight than those extracted with alkali/ethanol. In addition, an increment of incubation time resulted in a decreased thermal stability of hemicelluloses obtained from water-immersed sample.
authors.affiliation: Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
authors.forename: Shao-Ni
authors.initials: SN
authors.lastname: Sun
authors.forename: Xue-Fei
authors.initials: XF
authors.lastname: Cao
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Run-Cang
authors.initials: RC
authors.lastname: Sun
authors.forename: Gwynn Lloyd
authors.initials: GL
authors.lastname: Jones
authors.forename: Mark
authors.initials: M
authors.lastname: Baird
mesh_terms: D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D006109:Poaceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013227:Steam; D013696:Temperature; D014574:Uronic Acids / Q000032:analysis
chemical_list: D011134:Polysaccharides; D013227:Steam; D014574:Uronic Acids; C007916:hemicellulose
keywords: Fractionation; Hemicelluloses; Phyllostachys pubescens; Steam explosion; Water impregnation