- Professor of wood Chemistry and technology, interested in wood biopolymers, lignins in particular. Study various extractable molécules, among which polyphenols and terpenoids.edit
Research Interests:
Research Interests:
Forest trees are the world’s most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely... more
Forest trees are the world’s most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely recognized for their biological activity. These molecules are found in forest by-products, such as bark, buds, leaves, and knots, commonly ignored in forestry decisions. The present literature review focuses on in vitro experimental bioactivity from the phytochemicals of Myrianthus arboreus, Acer rubrum, and Picea mariana forest resources and by-products with potential for further nutraceutical, cosmeceutical, and pharmaceutical development. Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. Traditional forest management systems...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In this work, free-radical grafting was investigated in order to enhance the compatibility between lignins and polyolefins. High density polyethylene (HDPE) was used as the matrix and two types of industrial lignins were selected as... more
In this work, free-radical grafting was investigated in order to enhance the compatibility between lignins and polyolefins. High density polyethylene (HDPE) was used as the matrix and two types of industrial lignins were selected as eco-friendly fillers: Kraft lignin which represents most of the global lignin production, but lacks adequate applications; and organosolv lignin which has received increasing attention for its low molecular weight, homogeneity and sulfur-free characteristics. The compounds were produced by batch mixing, and were compression molded. From these samples, morphological, tensile and thermal properties were studied. The results show that incorporation of different lignins into HDPE yielded materials of different tensile behavior, but improvement in morphological and mechanical properties through free-radical grafting was obtained. Furthermore, free-radical grafting was found to decrease the thermal oxidation resistance and the crystallinity of the composites.
Research Interests:
Research Interests:
Research Interests: Chemistry, Complementary and Alternative Medicine, Plant Biology, Biology, Ethnopharmacology, and 15 moreMedicine, Humans, Glucose, Mice, Animals, AMPK, Protein kinase B, Plant extracts, Homeostasis, Hepatocytes, Oral Hypoglycemic Agents, Glucose Homeostasis, Cell Survival, Muscle cells, and Pharmacology and pharmaceutical sciences
Research Interests:
Research Interests:
Research Interests:
A dilute acid hydrolysis of rice husk (RH), wheat straw (WS), and their extractive-free residues was investigated with the objective of recovering the highest yield of xylose while keeping at minimum its conversion into furfural. The... more
A dilute acid hydrolysis of rice husk (RH), wheat straw (WS), and their extractive-free residues was investigated with the objective of recovering the highest yield of xylose while keeping at minimum its conversion into furfural. The hydrolysis conditions were determined for different concentrations of sulfuric acid and different reaction times at 121 °C. The pre-extraction with ethanol-water (1:1, v/v) was also examined as a parameter. Using response surface methodology, the optimum conditions for xylose production were identified as 1.8% of acid and 41.4 min of hydrolysis time for RH, while those for its counterpart EF-RH (extractives-free rice husks) were 1.0% acid concentration, for 60 min. The same conditions were also predicted for WS and its EF-WS. Under these conditions, the xylose yield was 79.6%, 82.8%, 94.3%, and 88.6% for RH, EF-RH, WS, and EF-RW, respectively. Under these conditions the minimal furfural yields obtained were 1.2% and 1.3% for RH and EF-RH, and 0.8% and 1...
Research Interests: Chemistry, Nuclear Chemistry, Xylitol, Bioconversion, Xylose, and 4 moreHydrolysis, Furfural, Bioresources, and husk
Research Interests:
Research Interests:
Research Interests:
AB ST RA CT Densification of wood leads to improvement of its mechanical properties. Specimens of Pinus radiata and Eucalyptus nitens wood were densified using heat, steam, and pressure to improve their mechanical properties and thus... more
AB ST RA CT Densification of wood leads to improvement of its mechanical properties. Specimens of Pinus radiata and Eucalyptus nitens wood were densified using heat, steam, and pressure to improve their mechanical properties and thus enhance their utilization. At a maximum steam pressure of 550 kPa and a maximum press hydraulic pressure ranging from 4.5 to 9 MPa, selected temperatures of 160°C, 180°C, and 200°C were used to check the mechanical properties and to identify the chemical composition of wood samples before and after densification. Densified wood samples showed markedly reduced hygroscopicity. The chemical changes in the wood constituents occurring during densification were characterized using FT-IR, Py-GC/MS, and XPS. According to the densification process between pine and eucalyptus, the results obtained showed that the densification effects were better for Eucalyptus nitens than for Pinus radiata. The FT-IR analysis revealed a high condensation index for pine lignin an...
Research Interests:
Birch bark represents an abundant, and currently under-utilised, natural resource. Yellow birch (Betula alleghaniensis), named also emblem tree of Quebec, is commercially important and one of the most widespread birch species in the... more
Birch bark represents an abundant, and currently under-utilised, natural resource. Yellow birch (Betula alleghaniensis), named also emblem tree of Quebec, is commercially important and one of the most widespread birch species in the region, but the use of its bark is limited. It is only used as a low value fuel source in solid wood products industries. Bark triterpene extractives such as lupeol, betulin and betulinic acid have been described to have high biological activity. They are products of high value, although their content in yellow birch is not sufficiently high. In this study, we investigated the triterpenoid composition not reported earlier of the outer bark of B. alleghaniensis. Three triterpenes not previously reported in the bark of yellow birch were identified as betulinic aldehyde, β-amyrin and β-amyrenone and a fourth is in the process of being identified.
Research Interests:
Vacuum freeze-drying of biological materials is one of the best methods of water removal, with final products of highest quality. The solid state of water during freeze-drying protects the primary structure and the shape of the products... more
Vacuum freeze-drying of biological materials is one of the best methods of water removal, with final products of highest quality. The solid state of water during freeze-drying protects the primary structure and the shape of the products with minimal volume reduction. In addition, the lower temperatures in the process allow maximal nutrient and bioactive compound retention. This technique has been successfully applied to diverse biological materials, such as meats, coffee, juices, dairy products, cells, and bacteria, and is standard practice for penicillin, hormones, blood plasma, vitamin preparations, etc. Despite its many advantages, having four to ten times more energy requirements than regular hot air drying, freeze-drying has always been recognized as the most expensive process for manufacturing a dehydrated product. The application of the freeze-drying process to plant-based foods has been traditionally dedicated to the production of space shuttle goods, military or extreme-spo...
Research Interests:
ABSTRACT Fast pyrolysis is a promising technology to promote wood biomass utilization. This thermochemical process produces mainly a liquid bio-oil. Currently, a direct application of bio-oil as fuel is limited due to its poor... more
ABSTRACT Fast pyrolysis is a promising technology to promote wood biomass utilization. This thermochemical process produces mainly a liquid bio-oil. Currently, a direct application of bio-oil as fuel is limited due to its poor physicochemical properties.
Research Interests:
There are several factors influencing a fundamental property of a wood species, the limit of hygroscopicity of wood (LH) or fiber saturation point (FSP). The effect of temperature upon the limit of hygroscopicity has been mentioned in... more
There are several factors influencing a fundamental property of a wood species, the limit of hygroscopicity of wood (LH) or fiber saturation point (FSP). The effect of temperature upon the limit of hygroscopicity has been mentioned in literature, but has not been precisely quantified. In this paper we have correlated the LHs with temperature of thermal pretreatment, taking also into account the properties of particular wood species, i.e. density and chemical composition. For our investigation we have selected the most important domestic wood species for industrial processing : oak, beech, poplar, fir and spruce. We have determined the limits of hygroscopicity by method of compression strength parallel to grain, for the following temperature ranges of thermal treatments, in dependence of wood species : for hardwoods from 20° to 80°C and for softwoods from 20° to 90°C. Our results demonstrate the general decrease of the limit of hygroscopicity with the increase of temperature of the thermal pretreatment of the examined wood species. Mathematical correlations have been evaluated on the basis of experimental data by polynomial regression statistical method. Wood density is another factor examined as influential upon the limit of hygroscopicity. We have determined the decrease of the LH with the increase of wood density, i.e. denser wood species have lower capacity for water adsorption. The differences obtained for the LHs between the examined wood species have been explained in relation to their chemical compositions. Our results indicate that cellulose is the major wood component determining its capacity for water adsorption.
Research Interests:
... 174.7 pinus peuce; Dk 543.5; Balkankiefer; Xylemoelharz; Analyse; Glc; Gc/ms; Terpentin; Kolophonium; Monoterpen-kohlenwasserstoffe; Harzsaeuren; Neutrale diterpene; Cembranoide. Language, English. Notes, 3 tables; 12 ref. Type,... more
... 174.7 pinus peuce; Dk 543.5; Balkankiefer; Xylemoelharz; Analyse; Glc; Gc/ms; Terpentin; Kolophonium; Monoterpen-kohlenwasserstoffe; Harzsaeuren; Neutrale diterpene; Cembranoide. Language, English. Notes, 3 tables; 12 ref. Type, Summary. Journal Title, Holzforschung. ...
Research Interests:
Thermally assisted Hydrolysis and Methylation (THM), and 2D-heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) spectroscopy were used to monitor the transformation of ramial chipped wood (RCW) from Gmelina... more
Thermally assisted Hydrolysis and Methylation (THM), and 2D-heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) spectroscopy were used to monitor the transformation of ramial chipped wood (RCW) from Gmelina arborea and Sarcocephalus latifolius, together with their organosolv lignins, following soil incubation in Benin (West Africa). Mesh litterbags containing RCW were buried in soils (10 cm depth) and were retrieved after 0, 6, 12 and 18 months of field incubation. Chemical analysis showed that total carbohydrate content decreased, while total lignin content increased as RCW decomposition progressed. Ash and mineral content of RCW increased significantly after 18 months of decomposition in soil. Significant N-enrichment of the RCW was determined following 18 months incubation in soils, reaching 2.6 and 1.9 times the initial N-content for G. arborea and S. latifolius. Results of THM showed that the S + G sum, corresponding to lignins, increased with RCW re...
Research Interests:
Research Interests:
ABSTRACT Holding wood pieces together by rotationally welded dowels can be used to make blockboard panels with the dowels inserted in the side of the wood substrate slats. The average results for both tensile and three-point bending tests... more
ABSTRACT Holding wood pieces together by rotationally welded dowels can be used to make blockboard panels with the dowels inserted in the side of the wood substrate slats. The average results for both tensile and three-point bending tests indicate that a 20 degrees dowel insertion angle yields strength results better than 10 degrees and 0 degrees insertion angles. Applied load vs deformation in the two types of tests showed that blockboard panel stiffness was greater for the panels with 20 degrees dowel insertion angle. (C) Koninklijke Brill NV, Leiden, 2011
Research Interests:
Research Interests:
Background: We have determined previously that the water extract of sugar maple bark contained an important quantity of a complex sugar. In this study, we investigated the organosolv pulping of pre-extracted bark to follow the acid... more
Background: We have determined previously that the water extract of sugar maple bark contained an important quantity of a complex sugar. In this study, we investigated the organosolv pulping of pre-extracted bark to follow the acid conversion of sugars into major products, furfural and 5-hydroxymethyl-2-furfural (HMF), while comparing the structures of organosolv lignins. Methods: The bark particles were pre-extracted with an ethanol–water mixture or water only. The extractives-free barks were then converted into cellulosic pulp and lignin by a patented organosolv process. The composition of residual liquor was determined by using HPLC-UV. Results: The pre-extraction with water was more efficient for complex sugars recovery than with the ethanol–water system. HMF was determined to be more abundant in residual liquor than furfural after ethanol–water pre-extraction while their quantities were comparable in the residual liquor after water pre-extraction. The higher yield of HMF from e...
Research Interests:
Research Interests:
Research Interests:
The aim of this study was to investigate the effects of heat and steam on the chemical properties of thermo-hygromechanical (THM)-densified sugar maple wood. The THM densification process was performed at two different temperatures (180... more
The aim of this study was to investigate the effects of heat and steam on the chemical properties of thermo-hygromechanical (THM)-densified sugar maple wood. The THM densification process was performed at two different temperatures (180 °C and 200 °C) with and without steam. The functional groups, surface chemical composition and internal structure and components of the control and densified samples were investigated using attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray photoelectron (XPS) spectroscopy and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The obtained results suggest that the THM densification treatment resulted in significant chemical changes on the wood surface. The results of the ATR-FTIR spectra confirmed the decomposition of hemicelluloses and the relative increase of cellulose and lignin contents on the wood surface. The Py-GC/MS and XPS results show an increase of the oxygen/carbon atomic (O/C) ratio, which indicated that che...
Research Interests:
Reported for its antioxidant, anti-inflammatory and non-toxicity properties, the hot water extract of bark was demonstrated to contain highly valuable bioactive polyphenols. In order to improve the recovery of these molecules, an... more
Reported for its antioxidant, anti-inflammatory and non-toxicity properties, the hot water extract of bark was demonstrated to contain highly valuable bioactive polyphenols. In order to improve the recovery of these molecules, an optimization of the extraction was performed using water. Several extraction parameters were tested and extracts obtained analyzed both in terms of relative amounts of different phytochemical families and of individual molecules concentrations. As a result, low temperature (80 °C) and low ratio of bark/water (50 mg/mL) were determined to be the best parameters for an efficient polyphenol extraction and that especially for low molecular mass polyphenols. These were identified as stilbene monomers and derivatives, mainly stilbene glucoside isorhapontin (up to 12.0% of the dry extract), astringin (up to 4.6%), resveratrol (up to 0.3%), isorhapontigenin (up to 3.7%) and resveratrol glucoside piceid (up to 3.1%) which is here reported for the first time for . Ne...
Research Interests:
Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients... more
Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients of these extracts, as well as their safety on human PLB-985 cells differentiated into neutrophils-like cells, were determined. Proximate analysis showed that both bark extracts were low in moisture and fat. Sugar maple bark extract (SM-BX) showed crude protein and ash content higher than those found in red maple bark extract (RM-BX). In addition, SM-BX had total sugars higher than those evaluated in RM-BX, while complex sugars (oligo- and/or poly-saccharides) were similarly abundant in both bark extracts. Furthermore, SM-BX demonstrated a wide array of vital minerals (K, Ca, Mg, P, Na, Fe and Cu) in quantity larger than that evaluated in RM-BX, whereas RM-BX have Zn and Mn levels higher than those found in SM-BX. Phytochemical analyses showed that ...
Research Interests:
Research Interests:
Research Interests:
The present study reports, for the first time, the results of the antioxidant capacity and the phenolic composition of a hot water extract from red maple buds (RMB), as well as its safety. In this regard and comparatively to antioxidant... more
The present study reports, for the first time, the results of the antioxidant capacity and the phenolic composition of a hot water extract from red maple buds (RMB), as well as its safety. In this regard and comparatively to antioxidant standards, this extract exhibits a significant antiradical capacity when tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH· ) and anion superoxide trapping assays. High-resolution mass spectrometric and nuclear magnetic resonance analyses permitted to determine for the first time, in red maple species, cyanidin-3-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-arabinoside, and quercetin. Also, the quantification of individual phenolics by high-performance liquid chromatography method revealed that ginnalin A at 117.0 mg/g is the major compound of RMB hot water extract. Finally, using flow cytometry evaluation, the extract of RMB was determined to have no toxicity neither to cause significant modification of apoptosis process, up to concentration of 100 μg/ml, on human peripheral blood neutrophils. These results allow anticipating various fields of application of RMB water extract.
Research Interests:
ABSTRACT Betula alleghaniensis and B. papyrifera are widely distributed in the province of Québec (Canada) and, since these trees are valuable exports for the local lumber industry, large amounts of their residual ligneous biomass are... more
ABSTRACT Betula alleghaniensis and B. papyrifera are widely distributed in the province of Québec (Canada) and, since these trees are valuable exports for the local lumber industry, large amounts of their residual ligneous biomass are available for further exploitation. Betula species are well known for their significant concentrations of triterpenes, some of which were recently discovered to present promising bioactivity. The secondary transformation of birch biomass could therefore become important for many industries, particularly the pharmaceutical industry. In the present study, extracts from birch sawdust were obtained using an optimised ultrasound-assisted extraction in which the careful choice of temperature permitted a selective extraction of the targeted triterpenes. Moreover, compared with the classical Soxhlet method, higher extraction yields were obtained in a shorter time. The lipophilic extracts obtained using dichloromethane as a solvent were analysed by GC-MS and the major compounds identified as lupane-type cyclic triterpenoids accompanied by the non-cyclic triterpene squalene. Numerous aliphatic long-chain fatty acids were also found in the extracts together with phytosterols. Betulonic acid and squalene, the major extract constituents for both B. alleghaniensis and B. papyrifera, are both bioactive molecules.
Research Interests:
... A. Cloutier Département des Sciences du Bois et de la Forêt, Faculté de Foresterie et Géomatique, Centre de Recherche sur le Bois, Université Laval, Quebec G1K7P4, Canada e-mail:tatjana.stevanovic@sbf ... For the blank, 0.3 mL... more
... A. Cloutier Département des Sciences du Bois et de la Forêt, Faculté de Foresterie et Géomatique, Centre de Recherche sur le Bois, Université Laval, Quebec G1K7P4, Canada e-mail:tatjana.stevanovic@sbf ... For the blank, 0.3 mL methanol was mixed with 2.7 mL of the reagent ...