THE CONTENTS OF PHENOLICS AND CELL WALL COMPONENT OF EUCALYPTUS PELLITA F. MUELL STEMWOOD AND BARK (original) (raw)
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Chemical Composition of the Stemwood from Eucalyptus pellita
Proceeding of 9th International Symposium of Indonesian Wood Research Society, 2019
The objectives of this research were to investigate the chemical composition of Eucalyptus pellita F. Muell stemwood. Wood powder from the middle part of two trees was successively extracted by dichloromethane, ethanol, and hot water. The content of dichloromethane, ethanol, and hot water extracts were 0.17 to 0.47 %, 2.56 to 3.16 %, and 0.68 to 1.20 %, respectively. Total phenolics content (TPC) were from 549.05±25.75 to 570.35±137.05 mg GAE/ g dried extract (ethanol extract) and 175.9±50.4 to 465.2±16.0 mg GAE/ g dried extract (hot water extract). Further, total flavanols content (TFC) from ethanol and hot water solution varied from 257.45±24.45 to 301.25±73.25 mg CE/ g dried extract and 52.5±2.75 to 113±32.9 mg CE/ g dried extract, respectively. It was observed that, TFC of ethanol extract increased from bark to heartwood. By GC-MS, the lipophilic constituents composed of fatty acids, sterols, steroids, and other components. Short-chain fatty acids and sterols were the most abundant of the lipid compositions. With the regard to cell wall components, the content of holocellulose, alpha-cellulose, and lignin were from 68.33 to 69.47 %, 45.63-47.27 %, and 32.31-32.80 %, respectively.
Determination of the Chemical Composition of Eucalyptus spp. for Cellulosic Pulp Production
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The chemical composition of wood is important to assess the quality of this raw material for the industry of cellulosic pulp production. The purpose of this work was to determine the chemical composition of Eucalyptus spp. grown for cellulosic pulp production. Ten Eucalyptus spp. clones with six years of age, located in the municipality of Itamarandiba, Minas Gerais, Brazil, were used. Quantification was obtained for extractives, monosaccharides, uronic acids, acetates, lignin, ash and the phenolic composition of the extracts. In average, clones showed around 2.7% extractives, with a predominance of polar compounds soluble in ethanol and water; 27.7% lignin and 0.3% ash. Glucose was the main sugar detected (64.2%), followed by xylose (19.3%). The main components of the extractives were steroids, fatty acids and aromatic acids, followed by smaller amounts of substituted alkanoic acids, fatty alcohols, glycerol derivatives and triterpenes. The ethanol–water extracts presented total ph...
Heartwood and sapwood samples from Eucalyptus globulus were characterized by Py-GC/MS and GC-FID in respect to composition and content of lignin. The pyrolysis lignin-derived compounds were assembled by groups:-units). Heartwood and sapwood had similar lignin content in an extractive-free basis (23.7% and 23.0%, respectively) and in lignin composition (S-units, 76.0% vs. 76.3%; G-units, 22.0% vs. 21.0%; H-units, 1.9% vs. 2.7%; S/G ratio 3.5 and 3.6). The wood samples were kraft pulped under isothermal conditions at 130 • C, 150 • C and 170 • C and several cooking times. Heartwood and sapwood behaved similarly. At 130 • C the delignification was slow with no significant selectivity in respect to lignin composition. At 150 • C and 170 • C the S-units were more susceptible to reaction and comparatively more removed, inducing a decrease of S/G ratio to 0.6. The main products to be extracted belong to " syringol " and " S-aldehydes, " while the residual lignin in pulps was enriched in " guaiacol, " " eugenol " (G-units), and " phenol " (H-units).