title: Isolation and characterization of hemicelluloses extracted by hydrothermal pretreatment.
abstract: The dewaxed sample from Triploid of Populus tomentosa Carr. was extracted by using organic alkaline solvent (Dimethylformamide, DMF) via hydrothermal pretreatment. Neutral sugar compositions and molecular weight analysis demonstrated that the hemicellulosic fractions with a higher Uro/Xyl ratio, namely the more branched hemicelluloses, had higher molecular weights. Interestingly, these results were different from the previous report, in which the ratio of Uro/Xyl in the water-soluble hemicellulosic fraction was more than that of the alkali-soluble hemicellulosic fraction. Spectroscopy (FTIR, (1)H NMR, (13)C NMR, and HSQC) analysis indicated that the hemicellulosic fractions were mainly composed of (1→4)-linked α-D-glucan from starch and (1→4)-linked β-D-xylan attached with minor amounts of branched sugars from hemicelluloses. In addition, thermal analysis implied that linear hemicelluloses showed more thermal stability than the branched ones during pyrolysis.
authors.affiliation: Institute of Biomass Chemistry and Technology, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, PR China. mg_ma@bjfu.edu.cn
authors.forename: Ming-Guo
authors.initials: MG
authors.lastname: Ma
authors.forename: Ning
authors.initials: N
authors.lastname: Jia
authors.forename: Jie-Fang
authors.initials: JF
authors.lastname: Zhu
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Peng
authors.forename: Run-Cang
authors.initials: RC
authors.lastname: Sun
mesh_terms: D004126:Dimethylformamide / Q000737:chemistry*; D006361:Heating / Q000379:methods*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification*; D032107:Populus / Q000737:chemistry* / Q000235:genetics; D057885:Triploidy; D014867:Water / Q000737:chemistry*
chemical_list: D011134:Polysaccharides; D014867:Water; C007916:hemicellulose; D004126:Dimethylformamide