Publications Scientifiques
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Item Chemical characterization of sapwood and heartwood of Fraxinus angustifolia growing in Algeria(Taylor & Francis, 2021) Mazri, Sandra; Benotmane, Benamar; Hachemi, Messaoud; Pranovich, Andrey; Willför, Stefan; Smeds, AnnikaThe result of this study is the chemical characterization of sapwood (SW) and heartwood (HW) of Fraxinus angustifolia native to Algeria. Lipophilic and hydrophilic extractives were isolated by means of an accelerated solvent extractor (ASE) using hexane and the acetone/water mixture respectively. The acid hydrolysis and methanolysis methods were used to determine cellulose and hemicelluloses contents. The Tappi Standards T 222 and UM 250 allowed Klason and acid-soluble lignin quantification respectively. Alkaline hydrolysis of wood samples followed by HPLC analysis was performed to determine the acetyl groups. The method detailed in TAPPI T 211 (2002) for determining the ash content was used. It was found that the SW and HW of Fraxinus A. had almost similar amounts of the main components, averaging 40.00 wt% cellulose, 28.00 wt% hemicelluloses within 18.00 wt% of xylan, 22.00 wt% lignin, 3% extractives and 0.83 wt% ash. However, the HW contained more triglycerides (0.08 wt%) than the SW (0.02 wt%). On the other hand, mannitol was the most predominant hydrophilic extractive in SW (1.60 wt%) than in HW (1.02 wt%). These findings are useful for practitioners in the paper, biofuel, cosmetics, food, pharmaceutical and chemical industries for the assessment of Fraxinus A. wood chemical treatment parametersItem Optimization of the extraction of galactoglucomannans from Pinus halepensis(DE GRUYTER, 2020) Benouadah, Nacera; Pranovich, Andrey; Aliouche, Djamel; Labidi, Jalel; Willför, StefanThe effectiveness of pressurized hot-water extraction conditions for obtaining galactoglucomannans (GGMs) from Pinus halepensis suitable for applications like coatings and films packaging was investigated. For this purpose, high molar masses with high yields are required, presenting a serious challenge for hot-water extraction processes. The extraction of GGMs was carried out in an accelerated solvent extractor (ASE) and the isolation was performed by precipitation in ethanol. Three temperatures in the range 160–180 °C and five extraction times 5–90 min were tested in order to optimize extraction parameters of GGMs, avoiding thermal and chemical degradation in hot-water. Total dissolved solids (TDS) were determined gravimetrically after freeze-drying and weight average molar masses (Mw) were determined by high-performance size exclusion chromatography (HPSEC). Total non-cellulosic carbohydrates were determined by gas chromatography (GC) after acid methanolysis. Free monomers were additionally analyzed by GC. Lignin in water extracts was measured by an ultraviolet (UV) method. Acetic acid was determined after alkaline hydrolysis of acetyl groups and analyzed by HPSEC. The main parameters influencing the extraction processes of the GGMs, namely, extraction time and temperature were studied. Optimal extraction parameters of GGMs were identified at 170 °C and 20 min extraction time, with average Mw of extracted fraction of 7 kDa leading to a GGM yield of approximately 56 mg g−1o.d.m, corresponding to 6% on dry wood basis.Item Chemical characterization of pinus halepensis sapwood and heartwood(Taylor & Francis, 2018) Benouadah, Nacera; Aliouche, Djamel; Pranovich, Andrey; Willför, StefanItem Analysis of extractives from Pinus halepensis and Eucalyptus camaldulensis as predominant trees in Algeria(2017) Benouadah, Nacera; Pranovich, Andrey; Aliouche, Djamel; Hemming, Jarl; Smeds, Annika; Willför, Stefan