References of "Richel, Aurore"
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See detailImpact d'un fractionnement soustractif sur la relation structure-fonction de la gomme de caroube
Gillet, Sébastien ULg; Blecker, Christophe ULg; Aguedo, Mario ULg et al

Poster (2013, July 02)

Le choix d'une température de fractionnement de la gomme de caroube va conditionner les caractéristiques des fractions obtenues et par conséquent les potentialité d'applications de ces dernières.

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See detailDéveloppement de nouveaux bioproduits générant une valeur ajoutée
Richel, Aurore ULg

Scientific conference (2013, May 30)

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See detailAmphiphilic structure-surface property relationships of monosaccharide-based surfactants
Razafindralambo, Hary ULg; Nicks, Francois ULg; Richard, Gaetan ULg et al

Poster (2013, April 08)

A set of monosaccharide-based renewable surfactants has been prepared, structurally checked, and systematically screened for different activities and functionalities. These compounds vary in the polar ... [more ▼]

A set of monosaccharide-based renewable surfactants has been prepared, structurally checked, and systematically screened for different activities and functionalities. These compounds vary in the polar head group, linker, and hydrophobic tail. Beyond the goal to find out the most potential valuable surfactants for each measurement, relationships between chemical structure, basic properties, and functionalities have been examined by comparing compounds differing in a single structural variable. In this paper, we show and explain the impact of the anomeric alpha or bêta, neutral or acid sugar derivatives, equatorial or axial position of hydroxyl group, alkyl chain substitute attachment position, number, and length on surface properties of sugar-based surfactants. [less ▲]

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See detailExtraction of lignin from Mediterranean agro-wastes: correlation between pretreatment conditions and lignin chemical structure
Manara, Panagiota; Zabaniotou, Anastasia; Richel, Aurore ULg

Conference (2013, January)

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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 detailExtraction de molécules à haute valeur ajoutée dans un but de maximisation de la valeur créée
Richel, Aurore ULg

Conference (2013)

Les recherches académiques dans le domaine du bioraffinage sont présentées au travers de schémas complets de valorisation. Les matières premières ciblées sont les résidus agricoles et forestiers, les ... [more ▼]

Les recherches académiques dans le domaine du bioraffinage sont présentées au travers de schémas complets de valorisation. Les matières premières ciblées sont les résidus agricoles et forestiers, les cultures énergétiques et les résidus des industries alimentaires. Le cracking et la conversion ultérieure de ces matières premières permettent l'obtention de biocarburants, bioproduits ou nouvelles formulations (filière biomasse-chimie). [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 detailDispersion of multiwalled carbon nanotubes in water by lignin
Rochez, Olivier; Zorzini, Gwendoline; Amadou, Julien et al

in Journal of Materials Science (2013), 48(14), 4962-4964

Multiwalled carbon nanotubes (MWCNT) can be stably dispersed in water with small amount of lignin. One-step dispersion in the 20.0 g/L concentration range is achieved at room temperature with excellent ... [more ▼]

Multiwalled carbon nanotubes (MWCNT) can be stably dispersed in water with small amount of lignin. One-step dispersion in the 20.0 g/L concentration range is achieved at room temperature with excellent electrical properties of MWCNT. Lignin is depicted to act as an anti-static agent. [less ▲]

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See detailLa lignine, une molécule d'intérêt issue du bioraffinage lignocellulosique
Richel, Aurore ULg

Conference (2012, November)

La mise sur pied d’initiatives de bioraffinage lignocellulosique génère des quantités importantes de lignines sous-exploitées. La lignine, l’une des molécules renouvelables les plus abondantes sur terre ... [more ▼]

La mise sur pied d’initiatives de bioraffinage lignocellulosique génère des quantités importantes de lignines sous-exploitées. La lignine, l’une des molécules renouvelables les plus abondantes sur terre, est un biopolymère fortement ramifié constitué d’unités aromatiques. La composition de ce polymère est fortement influencée par la nature du substrat lignocellulosique et par les conditions de cracking appliquées. Généralement destinée à des fins énergétiques, la lignine se voit aujourd’hui ouvrir de nouvelles pistes de valorisation à plus haute valeur ajoutée telles que des applications comme gaz de synthèse, additif dans le secteur de la plasturgie ou comme source de composés aromatiques destinés au secteur chimique. [less ▲]

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See detailProduction of surface-active agents and antioxidants from renewable resources under microwave heating
Richel, Aurore ULg

Conference (2012, November)

The non-energetic valorization of renewable resources using efficient and eco-friendly methodologies is the central axis of the “green chemistry” concept. In particular, the chemical conversion of ... [more ▼]

The non-energetic valorization of renewable resources using efficient and eco-friendly methodologies is the central axis of the “green chemistry” concept. In particular, the chemical conversion of carbohydrates arising from the hydrolysis of non-edible vegetable feedstock (i.e., lignocellulosic biomass and streams) is a widely explored thematic for the production of new high-added value materials. In this context, we report here on the development of a microwave heating methodology for the efficient production of carbohydrate-based and lignin-based chemicals with relevant antioxidant and surface-active properties. New effective synthetic protocols minimizing wastes and energy-consumption are proposed. Enhanced yields and selectivities are achieved after a few minutes of microwave heating using heterogeneous catalysts. The benefits of this microwave approach are highlighted in terms of yields, atom efficiency, environmental factor, and carbon efficiency. Up-scaling assays are also discussed. [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 detailGreen synthesis and antioxidant activity of new PEGylated ferulic acids
Nicks, Francois ULg; Richel, Aurore ULg; Richard, Gaetan ULg et al

in Tetrahedron Letters (2012), 53(19), 2402-2405

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both ... [more ▼]

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both reactive and solvent. Esterification with PEG400 and PEG1000 leads to original compounds soluble in all proportions in water. These new compounds display an antioxidant activity similar to that of ferulic acid. [less ▲]

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See detailLa lignine, une molécule d'intérêt issue du bioraffinage
Richel, Aurore ULg

in Chimie Nouvelle (2012), 111

The implementation of lignocellulosic biorefinery initiatives generates significant amounts of underexploited lignins. Lignin, one of the most abundant renewable molecules on earth, is a highly branched ... [more ▼]

The implementation of lignocellulosic biorefinery initiatives generates significant amounts of underexploited lignins. Lignin, one of the most abundant renewable molecules on earth, is a highly branched biopolymer consisting of aromatic units. Generally intended for energy purposes, lignin has nowadays opened new vistas for higher added-value applications such as syngas, additive in the plastics industry or as a source of aromatic compounds dedicated to the chemical sector. This article provides an update on this molecule and its potential applications. [less ▲]

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See detailEvaluation of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for second-generation lignin analysis
Richel, Aurore ULg; Vanderghem, Caroline ULg; Simon, Mathilde ULg et al

in Analytical Chemistry Insights (2012), 7

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted ... [more ▼]

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely CHCA (alpha-cyano-4-hydroxycinnamic acid), in combination with alpha-cyclodextrine, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions (m/z 100-600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal interunit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus (Miscanthus x giganteus) and Switchgrass (Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study. [less ▲]

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See detailCatalytic hydroprocessing of lignin under thermal and ultrasound conditions
Finch, Kenneth B.; Richards, Ryan; Richel, Aurore ULg et al

in Catalysis Today (2012), 196

Lignin isolated from Miscanthus x giganteus using acidic (FAL) and alkali (AL) conditions was thereafter subjected to the catalytic depolymerization under thermal or ultrasounds activation. The ... [more ▼]

Lignin isolated from Miscanthus x giganteus using acidic (FAL) and alkali (AL) conditions was thereafter subjected to the catalytic depolymerization under thermal or ultrasounds activation. The characterization of lignins was achieved by thermogravimetric analysis and FTIR. Three different classes of catalysts, containing nickel as active species, have been prepared in this scope: (i) nano-Ni by reduction of NiCl2 with NaBH4 under ultrasonication, (ii) Fe3O4-(NiMgAlO)x and (NiAlO)x by calcination of Mg(Ni)–Al hydrotalcite incorporated Fe3O4 followed by reduction with hydrogen, and (iii) NiO(111) nanosheets by reduction of Ni(NO3)2 with urea in benzyl alcohol. The catalysts were characterized by XRD and XPS techniques. Reduced mixed oxides displayed a moderate activity while a significant increase in conversion (up to 90%) was observed in the presence of nano-Ni(0). NiO(111) nanosheets catalysts performed very close to nano-Ni(0). The conversion and the mass distribution of the reaction products were strongly related to the procedure used for the extraction of ligning. In all the case AL led to a better depolymerization. The performances of the tested catalysts under ultrasound conditions were inferior to those tested under conventional heating conditions. The nature of the solvent was also found to be very important in this process. Thus, ionic liquid [BMIM]OAc led to the best results in autoclave conditions, and methanol under ultrasounds. [less ▲]

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See detailConversion of carbohydrates under microwave heating
Richel, Aurore ULg; Paquot, Michel ULg

in Chang, C.F. (Ed.) Carbohydrates - Comprehensive Studies on Glycobiology and Glycotechnology (2012)

The non-energetic valorisation of renewable resources using efficient and eco-friendly methodologies is the central axis of the "green chemistry" concept. In particular, the chemical and chemo-enzymatical ... [more ▼]

The non-energetic valorisation of renewable resources using efficient and eco-friendly methodologies is the central axis of the "green chemistry" concept. In particular, the chemical and chemo-enzymatical transformations of carbohydrates arising from the hydrolysis of non-edible vegetal feedstock (i.e., lignocellulosic biomass) are a widely explored thematic for the production of new high-added value materials, synthons, and platform chemicals. Since the seminal works of Gedye and Giguere in 1986, the use of microwaves as a non-conventional heating source has gained large attention in organic chemistry. Due to commonly observed acceleration in reactions rates and improved selectvities and yields, microwave heating has progressively emerged as a green chemistry technology. Minimizing both energy consumption (via the reduction of temperature and reaction times) and wastes (by improvement of selectivity), microwaves has enjoyed significant adoption by the research community. This chapter describes the use of microwave processes to mediate key reactions in the field of carbohydrates chemistry. Some examples of typical carbohydrates reactions (glycosylations, hydroxyl groups’ protection, etc.) under microwave conditions are displayed and highlight the benefits of this microwave approach in terms of yields, atom efficiency, environmental factor, and carbon efficiency. [less ▲]

Detailed reference viewed: 47 (21 ULg)