title: Studies on the starch and hemicelluloses fractionated by graded ethanol precipitation from bamboo Phyllostachys bambusoides f. shouzhu Yi.
abstract: Starch from bamboo Phyllostachys bambusoides f. shouzhu Yi evaluated by means of solid-state 13C CP/MAS NMR and X-ray diffraction showed a typical B-type pattern with a very low degree of crystallinity (10.9%). In addition to starch, alkali-soluble hemicelluloses were further fractionated by graded precipitation at ethanol concentrations of 0 (HA), 15, 30, 45, 60, and 75% (v/v). Chemical composition and structural features of the six hemicellulosic subfractions were investigated by a combination of sugar analysis, GPC, FT-IR, GC-MS, 1D (1H and 13C) and 2D (HSQC) NMR spectra, and thermal analysis. The results showed that the bamboo hemicelluloses were O-acetylated 4-O-methyl-glucuronoarabinoxylans (GAX) consisting of a linear (1→4)-β-D-xylopyranosyl backbone decorated with branches at O-3 of α-L-arabinofuranosyl (5-12 mol%) or at O-2 of 4-O-methylglucuronic acid units and acetyl groups (0.8-11 mol%). The molecular weights of these polysaccharides ranged between 13400 and 67500 g/mol, and the molar ratios of A/X and G/X increased with ascending ethanol concentrations. Moreover, xylo-oligosaccharides (XOS) with DP 1-6 were produced by enzymatic hydrolysis of hemicelluloses and the total yields of XOS were range of 21.5 to 40.6%. The structure-property relationships were also established in order to improve enzyme accessibility.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China.
authors.forename: Pai
authors.initials: P
authors.lastname: Peng
authors.forename: Feng
authors.initials: F
authors.lastname: Peng
authors.forename: Jing
authors.initials: J
authors.lastname: Bian
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Runcang
authors.initials: R
authors.lastname: Sun
mesh_terms: D031723:Bambusa / Q000737:chemistry*; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D000431:Ethanol / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis / Q000302:isolation & purification*; D011134:Polysaccharides / Q000032:analysis / Q000302:isolation & purification*; D013213:Starch / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D010936:Plant Extracts; D011134:Polysaccharides; D000431:Ethanol; C007916:hemicellulose; D013213:Starch