References of "Paquot, Michel"
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See detailFast and high yield recovery of arabinose from destarched wheat bran
Aguedo, Mario ULg; Vanderghem, Caroline ULg; Goffin, Dorothée ULg et al

in Industrial Crops & Products (2013), 43

Enzymatically destarched wheat bran (DWB) contained 13.8% of arabinose and 23.1% xylose. Up to a maximum of 70% of the arabinose was progressively released from DWB when heated at 80 or 100°C in media ... [more ▼]

Enzymatically destarched wheat bran (DWB) contained 13.8% of arabinose and 23.1% xylose. Up to a maximum of 70% of the arabinose was progressively released from DWB when heated at 80 or 100°C in media acidified with HCl. Whereas microwave irradiation at higher temperatures in pressure vessels could lead to higher yields of extraction. A Box-Behnken experimental design established an efficient model describing the effects of temperature, irradiation duration and pH on arabinose extraction. The pH appeared as the most important factor of the process. 4-5 min of microwave heating at 150ºC and pH 1 appeared as a fast and highly efficient method to recover more than 90% of the arabinose of DWB. When plotting the percentages of arabinose against the combined severity factors LogR’0 (calculated from the temperature/duration/pH conditions applied), two different fitting profiles were obtained for both the heating techniques. Under microwave heating, high free xylose’s release could also occur. The experimental design led to a quadratic model predicting the release of xylose from DWB. A range of conditions enabled to minimize xylose and hydrolyze around 50% of the total arabinose, yielding a high purity fraction. An alternative would be to release more than 90% of both arabinose and xylose, for further arabinose purification or for a common valorization of both pentoses. [less ▲]

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See detailComparative biochemical analysis during the anaerobic digestion of lignocellulosic biomass from six morphological parts of Williams Cavendish banana (Triploid Musa AAA group) plants
Kamdem, Irenee ULg; Hiligsmann, Serge ULg; Vanderghem, Caroline ULg et al

in World Journal of Microbiology & Biotechnology (2013)

We studied banana lignocellulosic biomass (BALICEBIOM) that is abandoned after fruit harvesting, and assessed its biochemical methane potential, because of its potential as an energy source. We monitored ... [more ▼]

We studied banana lignocellulosic biomass (BALICEBIOM) that is abandoned after fruit harvesting, and assessed its biochemical methane potential, because of its potential as an energy source. We monitored biogas production from six morphological parts (MPs) of the "Williams Cavendish" banana cultivar using a modified operating procedure (KOP) using KOH. Volatile fatty acid (VFA) production was measured using high performance liquid chromatography. The bulbs, leaf sheaths, petioles-midribs, leaf blades, rachis stems, and floral stalks gave total biogas production of 256, 205, 198, 126, 253, and 221 ml g-1 dry matter, respectively, and total biomethane production of 150, 141, 127, 98, 162, and 144 ml g-1, respectively. The biogas production rates and yields depended on the biochemical composition of the BALICEBIOM and the ability of anaerobic microbes to access fermentable substrates. There were no significant differences between the biogas analysis results produced using KOP and gas chromatography. Acetate was the major VFA in all the MP sample culture media. The bioconversion yields for each MP were below 50 %, showing that these substrates were not fully biodegraded after 188 days. The estimated electricity that could be produced from biogas combustion after fermenting all of the BALICEBIOM produced annually by the Cameroon Development Corporation-Del Monte plantations for 188 days is approximately 10.5 × 106 kW h (which would be worth 0.80-1.58 million euros in the current market). This bioenergy could serve the requirements of about 42,000 people in the region, although CH4 productivity could be improved. © 2013 Springer Science+Business Media Dordrecht. [less ▲]

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See detailEffects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces
Rabetafika, Holy-Nadia ULg; Bchir, Brahim ULg; Aguedo, Mario ULg et al

in Food and Bioprocess Technology (2013)

This study examined the influence of applied tech- nologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties ... [more ▼]

This study examined the influence of applied tech- nologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties (water-holding capacity (WHC), swelling capacity (SWC), oil-holding capacity (OHC)) and the colour of dietary fibre (DF) during the production of fibre concentrates from unusual cooked apple and pear pomaces. Thermogravimetric analysis (TGA) and optical microscopy were also performed to monitor process-induced modifica- tion. All the processing conditions affected the compositions and physicochemical properties of DF. The bleaching treat- ment induced the greatest changes on DF producing yellow cellulose-rich fibre concentrates with improved WHC from 3.2 to 10.0 g/g and improved SWC from 4.0 to 8.8 ml/g. Otherwise, reduction of the particle size influenced hydration properties and colours of DF. WHC and SWC tended to increase with the particle size whereas smaller granulometric size increased the lightness of fibres. Desugaring increased the DF content in both pomaces by 1.2-fold with slight modifica- tion of apple insoluble dietary fibre ratio. Fibre concentrates had improved WHC and SWC up to 1.4-fold. All processes had no significant effect (p < 0.05) on OHC of DF except with ultrafine apple fibre concentrates. Results showed that pro- cessing had overall positive effects on DF contents and hy- dration properties of pomaces from cooked fruits. Bleached fibre concentrates from apple pomace had the highest WHC (10.0 g/g) whereas that of pear had the highest fibre content (89.9 %). Fibres from cooked fruit pomaces may therefore be used as textural ingredients or functional foods. [less ▲]

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See detailEffect of New Synthetic PEGylated Ferulic Acids in Comparison to Ferulic Acid and Commercial Surfactants on the Properties of Wheat Flour Dough and Bread
Nicks, Francois ULg; Richel, Aurore ULg; Dubrowski, Thomas ULg et al

in Journal of the Science of Food and Agriculture (2013), 93(10), 2415-2420

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the ... [more ▼]

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the properties of wheat flour dough and bread were analyzed and compared with those obtained with ferulic acid and two commercial surfactants, diacetyl tartaric acid ester of mono- and diglycerides and sodium stearoyl lactylate. Farinographic and alveographic methods as well as weight, volume and bread firmness measurements were used for this purpose. <br /> <br />RESULTS: Such as ferulic acid, when the PEGylated derivatives were implemented in the dough (5000 ppm), it accelerated its breakdown and decreased its rheological properties. However, it allowed to avoid the important diminution of loaf volume observed when dough supplemented with ferulic acid was baked. That decrease in volume was related to the inhibition of the yeast (Saccharomyces cerevisae) by the unesterified ferulic acid. Moreover, two of the PEGylated ferulic acids even contributed to an increase of loaf volumes (5-6%) and demonstrated crumb softener properties. <br /> <br />CONCLUSION: The addition of ferulic acid in wheat flour dough caused the inhibition of the yeast, which resulted in decreased bread volume. That effect could be avoid by the esterification of ferulic acid with poly(ethylene glycol). [less ▲]

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See detailEnzymatic synthesis and surface properties of novel rhamnolipids
Nott, Katherine ULg; Richard, Gaetan ULg; Laurent, Pascal ULg et al

in Process Biochemistry (2013), 48

New rhamnolipids were obtained via the development of a synthesis procedure consisting of two biocatalyzed steps. In the first step, naringinase was used to introduce a primary alcohol function onto ... [more ▼]

New rhamnolipids were obtained via the development of a synthesis procedure consisting of two biocatalyzed steps. In the first step, naringinase was used to introduce a primary alcohol function onto rhamnose by glycosylation of 1,3-propanediol. In the second step, immobilized lipase B from Candida antarctica catalyzed the esterification of the primary hydroxyl group with mono- and di-carboxylic fatty acids of increasing chain length (from C8 to C14). For the monoic acids, the initial rate and 24 h yield decreased with increasing chain length. For the dioic acid, the number of carbon atoms of the acid did not influence these parameters. The new rhamnolipid obtained with tetradecanoic acid showed very good surface properties. At pH 5, it had a very low critical aggregation concentration of 1.70 M and it diminished water’s surface tension to 27.6 mN/m. It was also able to form stable insoluble monolayers. On the other hand, the rhamnolipid formed with tetradecanedioic acid showed far less interesting surface properties. [less ▲]

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See detailHydrolysis of starches and flours by sorghum malt amylases for dextrins production
Ba, Khady ULg; Aguedo, Mario ULg; Tine, Emmanuel et al

in European Food Research & Technology (2013)

Corn and wheat starches as well as wheat and cassava flours were hydrolyzed using sorghum malt at 65 °C for 6 hours. During these reactions, dextrose equivalent (DE) values were followed under 3 ... [more ▼]

Corn and wheat starches as well as wheat and cassava flours were hydrolyzed using sorghum malt at 65 °C for 6 hours. During these reactions, dextrose equivalent (DE) values were followed under 3 concentrations of sorghum malt and of calcium chloride. Wheat flour presented the highest DE values and cassava flour had the highest hydrolysis yield. Thus, different dextrins were produced in a pilot plant and were analyzed by HPSEC and HPAEC-PAD for their molecular weight distribution and oligosaccharides composition respectively. The results indicated that oligosaccharides with broad molecular weight distributions were present in the dextrins produced and that the proportion of maltose was very high. [less ▲]

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See detailCharacterization of sugar beet pectic-derived oligosaccharides obtained by enzymatic hydrolysis.
Combo, Agnan Marie Michel ULg; Aguedo, Mario ULg; Quiévy, N et al

in International Journal of Biological Macromolecules (2013), 52(1), 148-156

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See detailOptimization of Production and Preliminary Characterization of New Exopolysaccharides from Gluconacetobacter hansenii LMG1524
Valepyn, Emmanuel ULg; Berezina, Nathalie; Paquot, Michel ULg

in Advances in Microbiology (2012), 2(4), 488-496

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and ... [more ▼]

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and bacterial growth of Gluconace-tobacter hansenii LMG1524, and preliminary characterization of EPS was investigated. The highest EPS yields were obtained using glycerol and ammonium sulphate as carbon and nitrogen sources, respectively. The increase of ethanol concentration in the medium did not influence the EPS synthesis but reduced the bacterial growth. The optimum tem-perature and pH for polysaccharides production were respectively 25 °C and 5; whereas for cell growth were respec-tively 30 °C and 4. The optimal culture medium composition was determined as follows : 10 g/L sucrose, 0.892 g/L (NH4)2SO4, 0.34 g/L NaNO3, 3 mL acetic acid, 1.5 g/L KH2PO4, 1.5 g/L K2HPO4 and 0.6 g/L MgSO4. The polysaccha-rides produced were of 14 and 10 polymerization degrees (DP) and constituted mainly of glucose, galactose and man-nose, in relative percent of 36.36, 33.94 and 22.42, respectively. [less ▲]

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See detailSynthesis and physico-chemical studies of glycine betaine derivatives
Laurent, Pascal ULg; NSimba Zakanda, Francis; Mvumbi Lelo, Georges et al

Poster (2012, October 11)

Design of new surfactants is of considerable interest in order to obtain materials with specific physico-chemical properties for targeted applications. Among them, quaternary ammonium surfactants are ... [more ▼]

Design of new surfactants is of considerable interest in order to obtain materials with specific physico-chemical properties for targeted applications. Among them, quaternary ammonium surfactants are widely employed in pharmaceutical and cosmetic industries. Unfortunately, as a consequence of their widespread use and strong resistance to biodegradation, those chemical surfactants may persist in wastewater treatment systems at relatively high concentrations and can cause a disturbance of the ecological equilibrium. In this context, glycine betaine based surfactants are of increasing interest today thanks to their higher biodegradability and low environmental impact. For example, alkylbetaines and alkylamidobetaines are produced on the industrial scale and are used as amphoteric surfactants less irritating compared to sodium dodecylsulfate (SDS) in cosmetics. In this study, new surface-active agents based on glycine betaine and issued from the green chemistry are synthesized. Very simple synthetic methodologies led to different betaine derivatives (esters, thioesters, amides). Their physico-chemical properties are investigated in order to give insights about the key parameters to take into account for the formulation of betaine derived compound preparations for cosmetic or pharmaceutical purposes. [less ▲]

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See detailInfluence of steam explosion on physico-chemical properties and hydrolysis rate of pure cellulose fibers
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

in Bioresource Technology (2012), 121(221-227),

The aim of the present study is to compare the effect of different steam explosion treatments on physicochemical properties and hydrolysis rate of a pure bleached cellulose. The results showed that ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on physicochemical properties and hydrolysis rate of a pure bleached cellulose. The results showed that moderate steam explosion treatments (severity factor below 5.2) did not improve the enzymatic hydrolysis rate of the cellulose fibers. The characterization of the obtained samples showed an increase of the cellulose accessibility coupled with an increase of the overall crystallinity of the substrate. In these conditions, the higher accessibility is counterbalanced by the increased crystallinity. Indeed, a greater proportion of the substrat is accessible by only a fraction of the enzymatic complex (exo-glucanases) activities. When the severity factor reached 5.2, a decrease of the cellulose enzymatic hydrolysis rate was observed. In this case, TGA analysis showed an increase of the char level at the end of the pyrolysis which traduced an important thermal degradation of the samples. The thermal degradation of cellulose lead to an important change in substrate composition, which induced a decrease of the cellulose ratio available for hydrolysis and caused a decrease of the hydrolysis yields. [less ▲]

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See detailUse of new surface active carbohydrate esters for the synthesis of polyhipes in supercritical CO2
Boyère, Cédric ULg; Favrelle, Audrey; Grignard, Bruno ULg et al

Poster (2012, September 10)

see attachment

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See detailImprovement of the cellulose hydrolysis yields and hydrolysate concentration by management of enzymes and substrate input
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Blecker, Christophe ULg et al

in Cerevisia : Belgian Journal of Brewing and Biotechnology (2012), 37

In order to improve the hydrolysis of cellulose fiber and to obtain highly concentrated hydrolysate, two methods based on successive addition of enzyme and substrate were assessed. The first method, which ... [more ▼]

In order to improve the hydrolysis of cellulose fiber and to obtain highly concentrated hydrolysate, two methods based on successive addition of enzyme and substrate were assessed. The first method, which required only substrate addition, allowed to increase by 50% the hydrolysate concentration and to decrease by 30% enzyme units needed. The second method highlighted the ability to reach very high concentrated hydrolysate (up to 170 g/l) by simultaneous addition of enzyme and substrate. In parallel, relationships between some limiting factors and the yields of hydrolysis were investigated. In conclusion, viscosity evolution of cellulose suspension during hydrolysis step was investigated with an aim to improve the management of enzyme and substrate addition. [less ▲]

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See detailSynthesis of microsphere-loaded porous polymers by combining emulsion and dispersion polymerisations in supercritical carbon dioxide
Boyère, Cédric ULg; Léonard, Alexandre ULg; Grignard, Bruno ULg et al

in Chemical Communications (2012), 48(67), 8356-8358

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds ... [more ▼]

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds were tuned by performing dispersion polymerisations within their cavities filled with supercritical CO2. [less ▲]

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See detailOptimization of a formic/acetic acid treatment of beech wood for lignin extraction
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Conference (2012, August)

Lignocellulosic substrates are a promising alternative resource for the sustainable production of energy (biofuels), bio-based products and organic compounds. In the past, the extraction and recycling of ... [more ▼]

Lignocellulosic substrates are a promising alternative resource for the sustainable production of energy (biofuels), bio-based products and organic compounds. In the past, the extraction and recycling of cellulose (into fermentable glucose) constituted the central axis of lignocellulosic biorefinery processes. Degraded hemicelluloses and lignins were recovered as side-products with no possibilities of high-added value applications. Within the context of an integrated biorefinery, and for economic reasons, the recovery and the non-energetic valorization of lignins have opened recently new horizons. Lignin is a cross-linked phenolic polymer and is considered as potential alternative to petrochemical polymers or as a source of antioxidants for cosmetics and food industry, resins, chelating agent... As the final application of lignin depends on both extraction process and type of lignocellulosic sources, the development of fast and efficient physicochemical characterization methods is thus a prerequisite to optimize extraction processing conditions. In this study, beech wood particles (Fagus sylvatica L.) are delignified at atmospheric pressure by a formic acid/acetic acid/water mixture. Firstly, response surface methodology is used to optimize cooking time and temperature for delignification, pulp yield and concentration of degradation products (2-furfural and 5-hydroxymethylfurfural). The results highlight that best delignification is obtained in the highest cooking times and temperatures and that 5-hydroxymethylfurfural is produced during the formic/acetic acid treatment but is also degraded into 2-furfural. With the aim to develop an integrated biorefinery approach, multi-criteria optimization is used to find ideal cooking time and temperature (5h07, 104.2°C) leading to the maximization of delignification and pulp yield and to the minimization of 2-furfural production Finally, physicochemical and chemical structures of extracted lignins are found dependent on treatment conditions harshness. [less ▲]

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See detailIn vitro determination of prebiotic potential of sugar beet pulp extracted candidates and influence of production method
François, Emmanuelle ULg; Goffin, Dorothée ULg; combo, Agnan Marie-Michelle et al

Poster (2012, June 12)

Various prebiotic hydrolysates were produced starting from sugar beet pulp (SBP) using alternative solution to traditional acidic hydolysis. SBP pectin was first extracted by acid extraction and ethanol ... [more ▼]

Various prebiotic hydrolysates were produced starting from sugar beet pulp (SBP) using alternative solution to traditional acidic hydolysis. SBP pectin was first extracted by acid extraction and ethanol precipitation. Then two technics are used to produced pectic oligosaccharides (POS) : enzymatic hydrolysis (EnzPOS : Rapidase Smart (DSM) ; 50°C ; pH 5) and microwaves-assisted hydrolysis (MW1POS : 104°C/10min/pH 7; MW2POS : 110°C/15min/pH 7). Structural characterization of fractions gave rise to different structural profiles between the four products. Moreover, fermentation parameters obtained in-vitro (A, B, Rmax and Tmax) were also characteristic of the fractions and in favor of a tight relationship between POS structure and POS function. Finally, to avoid solvent use, POS production could be envisaged directly on SBP. Avoiding the step of acidic extraction will allow to meet the green chemistry principles. [less ▲]

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See detailUse of glycosurfactants for the synthesis of polyHIPES in supercritical carbon dioxide
Boyère, Cédric ULg; Favrelle, Audrey; Léonard, Alexandre ULg et al

Poster (2012, June 04)

The abstract is available as a pdf file.

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See detailEffect of air-drying conditions on physical and nutritional properties of osmotically pre-treated pomegranate seeds
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

Poster (2012, June 01)

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See detailDesign of sugar-based surface active agents for emulsion polymerization in supercritical carbon dioxide
Boyère, Cédric ULg; Favrelle, Audrey; Broze, Guy ULg et al

Conference (2012, May 10)

The use of aqueous dispersed media, such as emulsions, has many advantages over solution processes for chemical transformations and polymerization reactions, i.e. limited environmental impact, ease of ... [more ▼]

The use of aqueous dispersed media, such as emulsions, has many advantages over solution processes for chemical transformations and polymerization reactions, i.e. limited environmental impact, ease of products recovery and increased reaction rate. Emulsions are usually implemented from a water/organic solvent mixture in the presence of a surfactant. However, supercritical carbon dioxide (scCO2) (Pc =74 bars; Tc = 31°C) constitutes an interesting alternative to the traditional organic solvents in these heterogeneous systems because it is inexpensive, non-toxic, non-inflammable and environmentally friendlier. In this context, we developed a novel class of surfactants for the stabilization of H2O/scCO2 emulsions, i.e. fluorinated modified carbohydrates. The hydrophilic head of the surfactant consists in a sugar moiety whereas a fluorinated tail is specifically located in the scCO2 phase. The strategies for the synthesis of these carbohydrates esters rely on selective lipase-catalyzed modifications of sugars and on the versatile thiol-Michael addition reaction. The ability of these molecules to decrease the H2O/scCO2 interfacial tension and to stabilize such emulsions will be presented. Finally, high internal phase scCO2-in-water emulsion (HIPE) were prepared with these new surfactants and used as template for the acrylamide polymerization. The monomer is polymerized in the continuous aqueous phase before removing the CO2 droplets (at least 70 % of the total volume). The resulting permeable porous polymers, called polyHIPEs, exhibit highly interconnected voids (cfr SEM picture) and should be valuable in many applications including support for catalyst, filtration process, immobilization of proteins, etc. [less ▲]

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