References of "Richel, Aurore"
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See detailBio-based paints
Olive, Gilles ULg; Richel, Aurore ULg

Poster (2013, November 27)

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming ... [more ▼]

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming material, diluted in solvents. [less ▲]

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See detailOld inks: plant-based inks
Wymeersch, Noémie; Despy, Jessica; Bouchat, Isabelle et al

Poster (2013, November 27)

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A ... [more ▼]

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A significant example of this is the Cosquer cave (-19,000 to -27,000 years) located near Marseilles (France). Pigments and dyes can be classified into two broad categories: natural pigments and dyes and those called artificial. These categories are then subdivided into five families. The first one of these five families includes the mineral pigments. Among these we can find the clays (yellow ochre, red ochre, green clay, brown clay) and the stones like lapis lazuli (blue) and malachite (green). The second and third families gather the organic dyes and pigments. Those that have vegetal origins like indigo (blue), weld (yellow) and madder (red) compose the family 2 and those that have animal origins like cochineal (red) and kermes dyers (carmine) form the family 3. One family includes pigments and dyes stemming from chemical reactions such as verdigris or red lead (family 4) and the other one is made of the miscellaneous inks such as iron-gall type who are vegetal and mineral one (family 5). All these pigments, although they have been used for centuries, have been replaced by synthetic dyes from the oil industry at the end of the 19th century. Indeed, they have the advantage of reproducibility of the properties unlike natural pigments. But the scarcity of oil causes a renewed interest in natural preparations. In such purpose, our laboratory in conjunction with the Abbey of Villers-la-Ville has decided to study natural derivatives for inks and focuses in particular on the extraction of pigments from plants. [less ▲]

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See detailLignocellulosic biomass pretreatment impact on the extracted lignins chemical structure
Manara, Panagiota; Zabaniotou, Anastasia; Vanderghem, Caroline ULg et al

Poster (2013, October)

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See detailLignin as a raw material for industrial materials applications
Richel, Aurore ULg; Vanderghem, Caroline ULg; Jacquet, Nicolas ULg et al

Poster (2013, October)

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl ... [more ▼]

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl, syringyl or p-hydroxyphenyl) linked together by a panel of specific ether or carbon-carbon bonds.[1] Nowadays, large amounts of lignins and lignin-based wastes are available and originate either from the pulp and paper manufacturing or from the production of bioethanol from lignocellulose. [2] Typically, these lignins are dedicated to energetic purposes by combustion. In recent years however, novel axes for high added value applications have emerged and concern, notably, the use of lignin as performance products (e.g. polymer additives, binders) or specialty chemicals (e.g. surface-active agents) for materials applications.[3] Herein, several applications of lignin in materials sciences with industrial issues are presented. A correlation is established between the extraction processes from lignocellulosic materials and the chemical structure and physico-chemical properties of lignins.[4] Our research group has also developed new methodologies for the extraction of highly pure lignins from several starting materials, including food wastes, herbaceous raw materials and wood biomass. These methodologies include microwave-assisted extraction and two-step conventional pretreatment involving steam explosion. These methodologies are described in this presentation. [less ▲]

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See detailGrowth of Chlorella in vanillin enriched medium
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg

Poster (2013, August)

In this work the effect of different concentration of vanillin on the growth of Chlorella culture was evaluated. Two concentrations of vanillin: 60 mg/L and 300 mg/L in Bold Basal Medium (BBM) were tested ... [more ▼]

In this work the effect of different concentration of vanillin on the growth of Chlorella culture was evaluated. Two concentrations of vanillin: 60 mg/L and 300 mg/L in Bold Basal Medium (BBM) were tested and an inoculum from a two month Chlorella sp. (CCBA) culture was used. Vanillin at concentration of 60 mg/L showed to possess stimulating effect on Chlorella growth during 11 days of cultivation. Stimulation of Chlorella started on 3rd day of growth and was accompanied by 87% decrease of vanillin concentration within first 3 days of cultivation and its complete removal from growth media after 7 days. The acceleration of Chlorella growth in vanillin containing medium was detected due to biomass density, up to 1.2 times bigger than in the control culture, but also by measurement of chlorophyll content. Increased amount of chlorophyll content, up to 1.35 times higher than in control, was found between 4th and 11th day of cultivation. The response of Chlorella towards higher concentration of vanillin (300 mg/L) was different when compared to experiments where only 60 mg/L was used. During first 4 days of cultivation, strong inhibition of Chlorella exposed to 300 mg/L vanillin was observed and vanillin concentration maintained at the same initial concentration. During next days, a recovery effect occurred as biomass density and chlorophyll content gradually increased in comparison to the onset of growth and vanillin concentration decreased to 2 % of its initial value. Biomass density measured in Chlorella culture on 11th day was much higher than at the beginning of cultivation but still by 40% smaller than in control and by 50% smaller than in the culture growing in medium with 60 mg/L of vanillin. Chlorophyll content at the end of cultivation constituted 50% of control value and 35% of chlorophyll culture with 60 mg/L vanillin in medium. [less ▲]

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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)

Detailed reference viewed: 19 (9 ULg)
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 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 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 ▲]

Detailed reference viewed: 78 (23 ULg)