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  • Researchpp 461-471Matsunaga, Y., Wahyudiono, Machmudah, S., Askin, R., Quitain, A. T., Sasaki, M., and Goto, M. (2013). "Hydrothermal extraction and micronization of polysaccharides from Ganoderma lucidum in a one-step process," BioRes. 8(1), 461-471.AbstractArticlePDF

    Ganoderma lucidum (G. lucidum) is a mushroom-forming white rot fungus that contains a wide variety of bioactive components (glucans). In this study, G. lucidum was utilized for the extraction of polysaccharides by hot compressed water at a temperature of 160oC and a pressure of 4.0 MPa using a semi-batch system. Under these conditions, thermal softening of G. lucidum occurred, allowing the removal of the polysaccharides protecting other constituents in G. lucidum via hydrolysis. Next, the extract was directly atomized by spray drying to remove the water. Scanning electron microscope (SEM) images showed that the particles formed were spherical and dimpled or shriveled with diameters varying from 1 to 6 mm. Based on these results it is proposed that this process is applicable to isolate polysaccharides from other types of biomass and may result in advances in extraction technology to obtain plant biomass components.

  • Researchpp 472-486Zeng, X., Vishtal, A., Retulainen, E., Sivonen, E., and Fu, S. (2013). "The elongation potential of paper - How should fibres be deformed to make paper extensible?" BioRes. 8(1), 472-486.AbstractArticlePDF

    Elongation at failure is an important but underrated functional property of paper. Traditionally, elongation has been of specific importance for sack and bag paper grades. Mechanical treatments at high consistency are known to induce fibre deformations that contribute to the elongation of paper. However, it is not clear to what extent different fibre deformations can improve the elongation of paper. The aim of this work was to investigate the influence of three mechanical treatments on fibre and paper properties. The wing defibrator, the E-compactor, and the Valley beater were used for treating chemical softwood pulp. It was found that the type and intensity of mechanical treatments significantly affect the formation of fibre deformations, and thus the resulting properties of paper. The combination of high-consistency wing defibrator treatment and subsequent low-consistency valley beating provided paper with high elongation potential and good strength properties without impairing the dewatering properties.

  • Researchpp 487-498Yang, Q., Karlsson, O., Ahmed, S. A., and Morén, T. (2013). "Dimensional stability and water repellency of European aspen improved by oxidized carbohydrates," BioRes. 8(1), 487-498.AbstractArticlePDF

    Small samples from European aspen (Populus tremula L.) were impregnated with carbohydrates oxidized by Fenton’s reagent using water in a vacuum, followed by heating in an oven at 103 °C. An antiswelling efficiency (ASE) of around 45% for wood treated with oxidized glucose and 35% for wood treated with oxidized sucrose was obtained. Samples treated with oxidized carbohydrates gave water repellent effectiveness (WRE) values over 35%. The decrease in cell wall thickness during impregnation was about 18% less in the presence of oxidized glucose than samples only treated with Fenton’s reagent. An ASE of 20% for the wood samples that had been treated with oxidized glucose was obtained after 7 days of soaking in water. The reasons for the improvement in dimensional stability are discussed in this work.

  • Researchpp 499-514Dagnino, E. P., Chamorro, E. R., Romano, S. D., Felissia, F. E., and Area, M. C. (2013). "Optimization of the pretreatment of Prosopis nigra sawdust for the production of fermentable sugars," BioRes. 8(1), 499-514.AbstractArticlePDF

    The black carob tree (Prosopis nigra) is a particularly valued species in Chaco, Argentina on account of its hard wood. Finding a use for the sawdust, the main industrial residue of wood, could be useful within the furniture industry of any country in the tropics seeking to apply the biorefinery concept. For the conversion of wood carbohydrates to bioethanol, a pretreatment stage is necessary. The objective of this work was to find the acid pretreatment conditions that maximize the extraction of xylose with minimum degradation, while maximizing the concentration of glucans in the pretreated solid to obtain better enzymatic accessibility, using black carob tree sawdust as the raw material. The optimization was carried out by use of a central composite design (CCD) with two independent variables: the concentration of the sulfuric acid solution and the heating time. Optimal enzymatic hydrolysis occurred at the mean values of the tested acid solution concentration (1.2%) and after shorter heating times (10.2 min). The concentration of sugars after the enzymatic hydrolysis of the pretreated solid over a time period of 72 h was three times higher than the untreated solid.

  • Researchpp 515-529Pei, J., Zhang, Y., Zhang, F., Yu, X., and Yan, X. (2013). "Enhancing antimicrobial activity in unbleached kraft pulp using laccase and phenolic compounds," BioRes. 8(1), 515-529.AbstractArticlePDF

    Unbleached kraft pulp fibers were reacted with laccase in the presence of different phenolic compounds (isoeugenol, butyl p-hydroxybenzoate, p-coumaric acid, and ferulic acid) in order to confer them with new properties. After the enzymatic stage, antimicrobial tests demonstrated that the handsheets formed from the laccase/phenolic-treated pulp showed a greater efficacy against Gram-positive and Gram-negative bacteria compared to handsheet paper treated only with laccase and a control. Laccase in the presence of butyl p-hydroxybenzoate produced handsheets with the most significantly enhanced bactericidal effect. An analysis of scanning electron microscope images of the treated kraft pulps increased kappa numbers and surface features of the fibers. The reduction in the absolute value of the zeta potential of the pulps indicates that the phenolic compounds produce chemical cross-linking within the fiber surface. X-ray photoelectron spectroscopy shows that the lignin content of the pulp fiber surface increased after adding the laccase and phenolic compounds.

  • Researchpp 545-556Jiang, P., Zhang, Y., Shan, Z., and Zheng, Q. (2013). "Optimizing the extraction yield of polyprenols from needles of Cunninghamia lanceolata (Lamb.) Hook using response surface methodology and its antioxidative activities," BioRes. 8(1), 545-556.AbstractArticlePDF

    An improved optimization method was used, combining a single-factor experiment and Response Surface Methodology to optimize the medium for the extraction yield of polyprenols from the needles of Cunninghamia lanceolata (Lamb.) Hook . A three-factor, three-level Box-Behnken design was used with extraction temperatures, extraction times, and liquid-solid ratio as independent variables to understand and optimize the extraction yield of polyprenols. A mathematical model with a high coefficient of determination was obtained and could be employed to optimize polyprenols extraction. From the optimized values of extraction temperature 71.4 °C, extraction time 5.96 h, and liquid-solid ratio 9.3:1, the extraction yield of polyprenols was 1.22 ± 0.04% (N = 3), which agreed closely with the predicted value (1.27%). Besides, polyprenols were demonstrated to have a strong antioxidative ability in vitro. Scavenging percentages of superoxide radical and DPPH by polyprenols were up to 75.6% and 56.9%, respectively.

  • Researchpp 530-544Sint, K. M., Adamopoulos, S., Koch, G., Hapla, F., and Militz, H. (2013). "Wood anatomy and topochemistry of Bombax ceiba L. and Bombax insigne Wall.," BioRes. 8(1), 530-544.AbstractArticlePDF

    Wood anatomical characteristics, content of phenolic extractives, and topochemistry of two lesser known and underutilised hardwood species, Bombax ceiba and Bombax insigne were studied. Heartwood and sapwood material was obtained from logs originating from natural forests of Pyinmana District, Myanmar. The basic qualitative anatomical features agreed with descriptions reported for the species in other regions (e.g. India, Bangladesh, Southeast Asia). However, there were some light differences in the quantitative wood anatomical data among the regions due to the influence of environmental conditions. The amount of phenolic extractives obtained by gradual extraction with acetone-water was almost the same in heartwood and sapwood (about 1.2%) in B. insigne, while heartwood showed a higher amount (2.8%) than sapwood (2.5%) in B. ceiba. Topochemical distribution of lignin and phenolic deposits in heartwood tissues investigated by scanning UV microspectrophotometry (UMSP) revealed that B. insigne is more highly lignified than B. ceiba. For both species, a lower UV-absorbance by the fiber and ray cell wall as compared to that of the cell wall of vessels was observed. Also, phenolic compounds were mostly deposited in the lumina of parenchyma cells and vessels rather than in cell walls. The results further improve the knowledge on the wood anatomy and chemistry of the species and in this respect are useful in future research to broaden their utilisation potential.

  • Researchpp 557-570Barbaric-Mikocevic, Z., Plazonic, I., and Dzimbeg-Malcic, V. (2013). "The deinkability improvement of offset prints made from a two-side coated substrate," BioRes. 8(1), 557-570.AbstractArticlePDF

    This paper describes the improved removal of impurities (coating, ink/toner) from offset prints produced by digital printing of two-side coated paper. The substrates were printed by conventional and digital offset processes. Based on image analysis results it was established that deinking flotation is an inefficient method for ink particle removal from digital offset printed paper, but it is efficient for ink removal from conventional offset printed paper. On the other hand, pre-treatment with hydrogen peroxide solution gives better results for ink particle removal from digital offset prints than from conventional offset prints. Optimal parameters for hydrogen peroxide pre-treatment for both offset prints were chosen based on unprinted substrate mass loss results in the preliminary investigation. These results showed that hydrogen peroxide pre-treatment is more successful at removal of impurities in comparison with flotation deinking without pre-treatment.

  • Researchpp 571-580Wu, C.-L., Chang, H.-T., Hsui, Y.-R., Hsu, Y.-W., Liu, J.-Y., Wang, S.-Y., and Chang, S.-T. (2013). "Antioxidant-enriched leaf water extracts of Cinnamomum osmophloeum from eleven provenances and their bioactive flavonoid glycosides," BioRes. 8(1), 571-580.AbstractArticlePDF

    The study was designed to investigate the antioxidant activities of water extracts of C. osmophloeum leaves from eleven provenances (CO1-CO11) and their bioactive phytochemicals. Results revealed that leaf water extracts contained antioxidant phytochemicals and showed efficacy as antioxidants. Among varied leaf water extracts, water extract of CO4 showed the highest total phenolic content (160.9 mg/g) and superior free radical scavenging ability with the IC50 values of 10.3 and 16.9 μg/mL for DPPH and superoxide radical scavenging assays, respectively. It was also found to exhibit the best metal chelating ability and reducing power. According to the multiple spectral analyses, bioactive phytochemicals of leaf water extracts were flavonoid glycosides, including kaempferol-7-O-rhamnoside and kaempferol-3,7-O-dirhamnoside. Leaf water extracts of C. osmophloeum with high performance of antioxidant efficacy have great potential as a natural daily supplement.

  • Researchpp 581-591Shi, Z., Fu, F., Wang, S., He, S., and Yang, R. (2013). "Modification of Chinese fir with alkyl ketene dimer (AKD): Processing and characterization," BioRes. 8(1), 581-591.AbstractArticlePDF

    A process for the chemical modification of Chinese fir with alkyl ketene dimer (AKD) was studied. The hydrophobicity of the resulting products was evaluated by characterization of the equilibrium moisture content, water-surface contact angle, water absorption coefficient, and anti-swelling efficiency. The results indicated that when 5% AKD solution was used, the modified wood generally showed good hydrophobicity and improved dimensional stability. The result of boiling water and hexane extraction tests showed that the modified fir possessed very stable hydrophobicity.

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