title: Separation of polymeric galactoglucomannans from hot-water extract of spruce wood.
abstract: Two methods for separation of polymeric galactoglucomannans (GGMs) from a hot-water extract of spruce wood, i.e., membrane filtration and precipitation in ethanol-water, were compared. Filtration through a series of membranes with different pore sizes separated GGMs of different molar masses, from polymers to oligomers. Only polysaccharides were precipitated in ethanol-water. With the optimal water content of 5-15%, the precipitated amount was about 6% on wood basis. The average molar mass of the precipitated polysaccharides was 10-12kDa with a molar mass range of 4-20kDa. GGMs comprised about 80% of the precipitated hemicelluloses. Other precipitated polysaccharides were mainly arabinoglucuronoxylans and pectins (rhamnogalacturonans). Analysis of a lignin-free, ethanol-precipitated GGM preparation by (13)C NMR spectroscopy verified that it was structurally almost identical with a GGM-rich ethanol precipitate obtained from spruce wood by extraction at much milder conditions, 90°C for 60min.
authors.affiliation: Laboratory of Wood and Paper Chemistry, Process Chemistry Centre, Åbo Akademi University, Porthansgatan 3, FI-20500 Turku/Åbo, Finland. tsong@abo.fi
authors.forename: Tao
authors.initials: T
authors.lastname: Song
authors.forename: Andrey
authors.initials: A
authors.lastname: Pranovich
authors.forename: Bjarne
authors.initials: B
authors.lastname: Holmbom
mesh_terms: D011232:Chemical Precipitation; D000431:Ethanol / Q000737:chemistry; D005374:Filtration; D008031:Lignin / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000302:isolation & purification*; D008567:Membranes, Artificial; D009005:Monosaccharides / Q000032:analysis; D028222:Picea / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D011134:Polysaccharides / Q000302:isolation & purification*; D014934:Wood / Q000737:chemistry
chemical_list: D008351:Mannans; D008567:Membranes, Artificial; D009005:Monosaccharides; D010936:Plant Extracts; D011134:Polysaccharides; C443804:galactoglucomannan; D000431:Ethanol; C007916:hemicellulose; D008031:Lignin