References of "Blecker, Christophe"
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See detailAdsorption kinetics of total proteose peptone fractions at the air-water and n-dodecane-water interface
Karamoko, Gaoussou ULg; Razafindralambo, Hary ULg; Danthine, Sabine ULg et al

Poster (2012, March 26)

Surface properties of whey proteins are essential in applications requiring oil emulsification in an aqueous phase, or foam structure formation [1]. The adsorption at interfaces constitutes then an ... [more ▼]

Surface properties of whey proteins are essential in applications requiring oil emulsification in an aqueous phase, or foam structure formation [1]. The adsorption at interfaces constitutes then an approach of the physico-chemical mechanisms of foaming and emulsifying properties. Proteose-peptone is the minor fraction of whey's protein, thermoresistant and acid-soluble protein fraction extracted from milk [2], and known for its interesting surface properties [3]. In this study, the TPP fractions were extracted from skimmed milk UHT (milk TPP) and whey protein concentrate (WPC TPP). Their adsorption kinetics at the air-water and n-dodecane-water interfaces was investigated by the drop volume tensiometer method. Protein solutions of 1% (w/v) were <br />characterized under dynamic condition at various pH (4.0; native pH 4.67- 4.70 and 7.0). Milk TPP showed the lowest values as well as a faster reduction in surface tension at both considered interfaces. Therefore, TPP were found to e effective as surfactants. These results let us to presage good emulsifying and foaming properties of milk TPP compared to WPC TPP. The considerable influence of pH and extraction source on proteose-peptone's interfacial property have been highlighted. [less ▲]

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See detailImpact of the alkyl chain carbon atom number of uronic acid-derivative surfactants on interfacial and colloidal systems
Razafindralambo, Hary ULg; Richard, Gaetan ULg; Laurent, Pascal ULg et al

Poster (2012, March 26)

Uronic acid-derivative surfactants represent today an attractive group of Carbohydrate-based amphiphilic compounds for both fundamental and practical reasons [1,2]. In the continuity of our screening of ... [more ▼]

Uronic acid-derivative surfactants represent today an attractive group of Carbohydrate-based amphiphilic compounds for both fundamental and practical reasons [1,2]. In the continuity of our screening of their basic properties, and the approach in establishing relationships between their structure and properties [3,4], the impact of the alkyl chain carbon atom number on interfacial and colloidal systems has been systematically investigated. In this communication, the effect of odd-even number of carbon atom from C11 to C18, and the particular behavior of long chain derivatives on interfacial properties, as well as their impact on the formation and stability of colloidal systems, are presented. Experimental approaches have been conducted by investigating their properties and behaviors at gas-liquid and liquid-liquid under dynamic, equilibrium, and oscillatory interfacial conditions. Results are completed by and discussed with single molecule models established by theoretical approaches. [1] Razafindralambo, H.;Blecker, C.; Paquot, M., Screening of Basic Properties of Amphiphilic Molecular Structures for Colloidal System Formation and Stability. In Amphiphiles: Molecular Assembly and Applications, American Chemical Society: 2011; Vol. 1070, pp 53-66. [2] Laurent, P.; Razafindralambo, H.; Wathelet, B.; Blecker, C.; Wathelet, J.; Paquot, M., Synthesis and Surface-Active Properties of Uronic Amide Derivatives, Surfactants from Renewable Organic Raw Materials. J. Surfactants Deterg. 2011, 14, 51-63. [3] Razafindralambo, H.; Richel, A.; Wathelet, B.; Blecker, C.; Wathelet, J.; Brasseur, R.; Lins, L.; Miñones, J.; Paquot, M., Monolayer properties of uronic acid bicatenary derivatives at the air-water interface: effect of hydroxyl group stereochemistry evidenced by experimental and computational approaches. Physical chemistry chemical physics: PCCP 2011, 13 15291-15298. [4] Razafindralambo, H.; Blecker, C.; Mezdour, S.; Deroanne, C.; Crowet, J.; Brasseur,R.; Lins, L.; Paquot, M., Impacts of the Carbonyl Group Location of Ester Bond on Interfacial Properties of Sugar-Based Surfactants: Experimental and Computational Evidences. The journal of physical chemistry. B 2009, 113, 8872-8877. [less ▲]

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See detailL'entomophagie basée sur la production locale d'insectes comestibles : sommes-nous prêts ?
Sablon, Ludovic ULg; Alabi, Taofic Abdel Fabrice ULg; Drugmand, Didier et al

Poster (2012, March 07)

Les perspectives d’évolution de la population mondiale annoncent un accroissement continu menant à un niveau supérieur à 9 milliards d’individus d’ici 2050. Cette augmentation correspondra inévitablement ... [more ▼]

Les perspectives d’évolution de la population mondiale annoncent un accroissement continu menant à un niveau supérieur à 9 milliards d’individus d’ici 2050. Cette augmentation correspondra inévitablement à des besoins alimentaires accrus au niveau mondial. Même si des spécificités en terme de produits consommés et de disponibilités – facilités de productions varient d’une région à une autre, la limitation des superficies à consacrer aux productions agricoles, notamment dans le cadre des ressources animales est une constante. Il ne sera pas possible d’assurer des productions animales conventionnelles pour fournir les ressources nécessaires aux populations humaines à venir. Bien que les produits animaux comme sources de nutriments doivent être développés, il s’agit maintenant de se tourner vers des filières alternatives pour maximiser les ressources végétales utilisées en élevage, tout en minimisant l’espace nécessaire et les effets sur l’environnement, notamment en terme de résidus et polluants potentiels. L'entomophagie, ou le fait de consommer des insectes comme source alimentaire d’origine animale, est connue et pratiquée dans de nombreuses régions du monde depuis des siècles. A chaque situation locale, une solution entomologique comme ressource alimentaire peut être appliquée : par la collecte dans la nature ou par le développement d’élevage d’espèces indigènes. Si l’entomophagie est peu appliquée en Europe, c’est sans doute d’une part lié à une absence dans nos mœurs alimentaires et d’autre part lié à la diversité et l’abondance d’autres ressources animales plus conventionnelles dans notre référentiel occidental. Au vu de l’état prévisionnel de la difficulté à produire les ressources alimentaires animales dans un futur proche, peut-être est-il temps de ne plus considérer les insectes comme uniquement nuisibles et négatifs mais plutôt comme de nouvelles espèces à développer par exemple dans des productions industrielles. Si la taille de ces animaux d’élevage reste réduite, leurs capacités de reproduction, leurs courtes durées de développement et les taux de conversion de la biomasse végétale utilisée comme aliments nous permettent d’envisager des unités de production de tonnes de biomasses animales. En plus de cet aspect quantitatif, plusieurs paramètres qualitatifs font de nombreux insectes des ressources utiles notamment en terme de protéines (et plus particulièrement en terme de composition en acides aminés plus rares) et de lipides (avec une majorité d’acides gras insaturés, des ratios omégas 3 et 6 intéressants, l’absence de cholestérol,…). Chez nous l'entomophagie est encore méconnue même si l'on peut constater un intérêt croissant notamment ces derniers mois. Entre curiosité gustative, éveil environnementaliste lié au faibles quantités de résidus liées à la production d’insectes vis-à-vis d’autres élevages, ou efficacité de transformation de ressources végétales limitées, de plus en plus de personnes souhaitent franchir le pas de ne plus regarder mais bien goûter de l’insecte. Dans le cadre de plusieurs études menées à Gembloux Agro-Bio Tech – Université de Liège ainsi qu’à l’Insectarium Jean Leclercq – Hexapoda à Waremme, certains aspects socio-culturels liés à une diversité de préparations à base d’insectes ont été investigués. Des tendances nettes sur les critères menant à l’acceptation ou le refus catégorique de manger de l’insectes ont ainsi été déterminés. Aussi, des formulations particulières peuvent également être ciblées pour favoriser l’appréciation de la dégustation d’insectes. Face au défi alimentaire du futur et à l'intérêt croissant pour l'entomophagie dans diverses régions dont l’Europe, l’élevage industriel d’insectes constitue une piste sérieuse pour fournir une part non négligeable de produits animaux afin d’assurer des ressources notamment de divers nutriments pour les populations humaines. Diverses recherches sont actuellement en cours tant sur les aspects techniques de production que sur les approches socio-culturelles. Nul doute que d’ici quelques années, entiers ou fractionnés les insectes feront partie de nos régimes et habitudes alimentaires. [less ▲]

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See detailSTEAM EXPLOSION : PROCESS AND IMPACT ON LIGNOCELLULOSIC MATERIAL
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2012, March 01)

Steam explosion is a thermomechanochemical process which allows the breakdown of lignocellulosic structural components by steam heating, hydrolysis of glycosidic bonds by organic acid formed during the ... [more ▼]

Steam explosion is a thermomechanochemical process which allows the breakdown of lignocellulosic structural components by steam heating, hydrolysis of glycosidic bonds by organic acid formed during the process and shearing forces due to the expansion of the moisture. The process is composed of two distinct stages: vapocracking and explosive decompression. Cumul effects of both phases include modification of the physical properties of the material (specific surface area, water retention capacities, color, cellulose crystallinity rate,…), hydrolysis of hemicellulosic components (mono and oligosaccharides released) and modification of the chemical structure of lignin. These effects permit the opening of lignocellulosic structures and increase the enzymatic hydrolysis rate of cellulose components in the aim to obtain fermentable sugars used in second generation biofuels process. [less ▲]

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See detailINFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2012, March 01)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity [less ▲]

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See detailEffect of physicochemical characteristics of cellulosic substrates on enzymatic hydrolysis by means of a multi-stage process for cellobiose production
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Danthine, Sabine ULg et al

in Applied Biochemistry and Biotechnology (2012), 166(6), 1423-1432

The effect of two types of cellulose, microcrystalline cellulose and paper pulp, on enzymatic hydrolysis for cellobiose production was investigated. The particle size, the relative crystallinity index and ... [more ▼]

The effect of two types of cellulose, microcrystalline cellulose and paper pulp, on enzymatic hydrolysis for cellobiose production was investigated. The particle size, the relative crystallinity index and the water retention value were determined for both celluloses. A previously studied multistage hydrolysis process that proved to enhance the cellobiose production was studied with both types of celluloses. The cellobiose yield exhibited a significant improvement (120% for the microcrystalline cellulose and 75% for the paper pulp) with the multistage hydrolysis process compared to continuous hydrolysis. The conversion of cellulose to cellobiose was greater for the microcrystalline cellulose than for the paper pulp. Even with high crystallinity, microcrystalline cellulose achieved the highest cellobiose yield probably due to its highest specific surface area accessible to enzymes and quantity of adsorbed protein. [less ▲]

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See detailCarbohydrate-based surfactants: structure-activity relationships
Razafindralambo, Hary ULg; Blecker, Christophe ULg; Paquot, Michel ULg

in Nawaz, Zeeshan; Naveed, Shahid (Eds.) Advances in Chemical Engineering (2012)

The aim of the present contribution is: (1) to review CBS in terms of structural classification based on their molecular size (mono-, oligo-, polymeric surfactants), geometry (standard, bipolar or ... [more ▼]

The aim of the present contribution is: (1) to review CBS in terms of structural classification based on their molecular size (mono-, oligo-, polymeric surfactants), geometry (standard, bipolar or bolaform, and gemini surfactants), and the nature of the polar headgroup (charged or not, cyclic or not), the apolar tail (number and length of alkyl chain), and the linker (amide, ester, ...) and/or the spacer; (2) to present systematically results on structure- activity relationships of uronic acid derivatives (UADs), a particular class of carbohydrate-based surfactants. These concern the impact of each structural entity including the polar headgroup (stereochemistry), apolar tail (chain length, number, and unsaturation), and linkage/spacer, on the performance of UADs to change surface properties, and possibly, to form and stabilize colloidal systems. [less ▲]

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See detailContribution to the study of physicochemical and functional properties of hemicelluloses and xylooligosaccharides (XOS) extracted from rapeseed meal
Mertens, Cécile ULg; Paquot, Michel ULg; Destain, Jacqueline ULg et al

Poster (2012, February 08)

Rapeseed meal is one of the main industrial co-products from agriculture in Belgium, with more than 30 000 T produced each year. Beside its agricultural and energetic applications, new paths of ... [more ▼]

Rapeseed meal is one of the main industrial co-products from agriculture in Belgium, with more than 30 000 T produced each year. Beside its agricultural and energetic applications, new paths of valorization are being developed in order to add value to the rapeseed meal, usually by extraction of interesting molecules. In this thesis project, the aimed molecules are hemicelluloses, which are obtained via a global fractionation method that is being developed and optimized, constituting the first part of this project. Indeed, while rapeseed meals are globally already well exploited (mainly for their feed value), rapeseed hemicelluloses have not yet been studied for food application. Yet, hemicelluloses can be used as food additives (thickener, stabilizer, etc) mainly in bakery products. The literature being incomplete regarding the chemical structure of rapeseed hemicelluloses, one of the objectives of this project is to study their physicochemical properties, in regard with their technofunctional properties. Rapeseed hemicelluloses can also be used as raw material to produce an emergent type of prebiotic: xylooligosaccharides (XOS). These molecules can be introduced as well in the food supplement sector. Their production will be achieved by enzymatic hydrolysis, for a polymerization degree between two and five. Thus, the production and the physicochemical and technofunctional characterization of rapeseed XOS constitute the last objective of this project. This thesis is part of the SYNBIOFOR project, which aim is to create new symbiotic ingredients. [less ▲]

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See detailLes crèmes végétales : une alternative aux crèmes laitières
Anihouvi, Prudent; Danthine, Sabine ULg; Karamoko, Gaoussou ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 344-359

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See detailComposition of by-products from cooked fruit processing and potential use in food products
Aguedo, Mario ULg; Kohnen, Stephan; Rabetafika, Holy-Nadia ULg et al

in Journal of Food Composition and Analysis (2012), 27

The process that produces Lie`ge syrup (apple butter-like) results in high amounts of residues from cooked apples, pears and sun-dried dates. These unusual fruit by-products were studied for their ... [more ▼]

The process that produces Lie`ge syrup (apple butter-like) results in high amounts of residues from cooked apples, pears and sun-dried dates. These unusual fruit by-products were studied for their composition in total proteins and fats, dietary fiber (DF) and their content in total and free monosaccharides. All three by-products contained around 20% of total non-cellulosic monosaccharides and around 10% of free monosaccharides. According to two different methods, DF accounted for 70% of the dry weight (DW) with an insignificant soluble fraction; pectin represented 2–3% of DW. Apple and pear residues were composed mainly of cellulose, whereas lignin was the main fraction for dried date. The polyphenolic content and the antioxidant activity of the three products were also assessed and the values showed that their antioxidant characteristics were comparable to that of various raw fruits. No phenolic acids were detected, indicating that the cooking process resulted in their extraction. The lyophilized and ground residues exhibited high water holding capacities (between 5.2 g water per g DW for pear and 8.6 for apple) and average oil holding capacities (around 2.5 g oil per g DW), whereas their color was light brownish as shown by the L*, a*, b* coordinates determined. These data open the possibility to contemplate new specific and niche applications for such by-products. Besides, it provides information about the effects of a cooking process on apple and pear pomaces, as well as on an unusual residue from a dried fruit (date). [less ▲]

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See detailScaphandre La science rencontre l'art: L'art
Haubruge, Eric ULg; Bay, Daniel ULg; Semal, Jean et al

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

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See detailInfluence of the water content in the synthesis of fructose laurate by immobilized lipase B of Candida antarctica (Novozym 435)
Olive, Gilles ULg; Pompeu Torezan, Gabriela A.; Blecker, Christophe ULg

in Bulletin de la Société Royale des Sciences de Liège (2012), 81(2012), 82-89

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved ... [more ▼]

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved, which is almost the same value as in the case of transesterification where no water as by-product is produced (74.6 %). The conversion rate of these reactions can be modeled as a function of the initial water content by a three-parameter power law for the esterification and by an exponential law for the transesterification. The influence of the water content on the mono over di-ester ratio will also be discussed to a lesser extent. [less ▲]

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See detailSynthèse enzymatique d'esters de fructose
Olive, Gilles ULg; Pompeu Torezan, Gabriela; Blecker, Christophe ULg

in Comptes Rendus Chimie (2012), 15(11-12), 1037-1047

The enzymatic synthesis of esters is well documented in the literature. A number of parameters have been revised to optimize the operating conditions, in view of a more industrial approach. The ... [more ▼]

The enzymatic synthesis of esters is well documented in the literature. A number of parameters have been revised to optimize the operating conditions, in view of a more industrial approach. The experimental conditions presented here are now superior to those of literature and the yields of esters show 78% of fructose laurate. Analytical methods have been perfected and rapid methods (based on different TLC conditions depending on the desired information), accurate methods (based on HPLC) and several purification methods were developed. [less ▲]

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See detailKinetics of the hydrolysis of polysaccharide galacturonic acid and neutral sugars chains from flaxseed mucilage
Happi Emaga, Thomas; Rabetafika, Holy-Nadia ULg; Blecker, Christophe ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 139-147

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See detailEnzymatic process development for the extraction of ferulic acid from wheat bran
Giet, Jean-Michel ULg; Blecker, Christophe ULg

Poster (2012)

The agro-industries generate each year thousands of tons of by-products, such as cereal bran or sugar beet pulps. For instance, Walloon wheat transformation industry provides annually about 200.000 tons ... [more ▼]

The agro-industries generate each year thousands of tons of by-products, such as cereal bran or sugar beet pulps. For instance, Walloon wheat transformation industry provides annually about 200.000 tons of bran. Most of those by-products are under-valorized as cattle feed. By the use of biorefinery, this biomass may constitute a renewable source for various value-added molecules like dietary fibres, proteins, antioxidants, and more. [less ▲]

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See detailL'homme produit - L'alimentation
Blecker, Christophe ULg

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre - La science rencontre l'art (2012)

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See detailLiquid Crystalline Phases Induced by the Hydroxyl Group Stereochemistry of Amphiphilic Carbohydrate Bicatenary Derivatives
Razafindralambo, Hary ULg; Richel, Aurore ULg; Paquot, Michel ULg et al

in Journal of Physical Chemistry B (2012), 116(13), 3998-4005

Liquid-crystals (LC) may exist in different phases depending upon the orientational and positional orders of molecules in the material. Here, we demonstrate that the class of LC state induced by ... [more ▼]

Liquid-crystals (LC) may exist in different phases depending upon the orientational and positional orders of molecules in the material. Here, we demonstrate that the class of LC state induced by amphiphilic carbohydrate bicatenary derivatives is strictly a hydroxyl group stereochemistry-dependent. This statement results from the experimental and theoretical investigations of surface film (2D) and bulk solid (3D) thermal behavior of synthetic stereoisomers n-tetradecyl (-D-n-tetradecyl) galacto- and gluco-pyranosiduronate, with an axial (GalA-C14/14) or equatorial (GlcA-C14/14) hydroxyl group at the fourth carbon, respectively. Surface pressure-area isotherms (283 K to 310 K), differential scanning calorimetry thermograms (223 K to 573 K), and polarized optical textures (298-363 K) reveal that GlcA-C14/14 organizes as a smectic LC-like phase (positional or lateral order) whereas the analogous stereoisomeric GalA-C14/14 behaves as a nematic LC-like phase (orientational order). Thermodynamic investigations and molecular dynamics models computed under similar temperature conditions provide consistent data with physical properties resulting from experimental approaches. [less ▲]

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See detailAgronomical factors influencing the legumin/ vicilin ratio in pea (Pisum sativum L.) seeds
Mertens, Cécile ULg; Dehon, Lydie; Bourgeois, Audrey et al

in Journal of the Science of Food and Agriculture (2012)

BACKGROUND: Many research studies have investigated the impact of agronomical factors on the protein content of pea (Pisum sativum). This study aimed to establish if a correlation exists between protein ... [more ▼]

BACKGROUND: Many research studies have investigated the impact of agronomical factors on the protein content of pea (Pisum sativum). This study aimed to establish if a correlation exists between protein content and legumin/vicilin (L/V) ratio in pea seeds and to identify agronomical factors that have an impact on this ratio. RESULTS: The L/V ratio was positively correlated with protein content (r = 0.58, P ≤ 0.01), but no linear regression was applicable (adjusted R² = 0.31). Both variety and cultivation year had a highly significant effect on the ratio (P < 0.001). The interaction between these two factors was also highly significant (P < 0.001), some varieties being less sensitive to climatic conditions than others. Cultivation location had a highly significant effect (P < 0.01). There was no interaction between variety and location. Seeding density had a highly significant effect on the ratio (P < 0.01),with a saturation effect above 60 seeds/m². CONCLUSION: Further studies should establish if a linear regression model can be applied to pea varieties independently. Varieties with a stable L/V ratio can prove to be useful in the food industry. Other agronomical factors (soil type and seeding density) should be considered for the production of pea seeds with a specific L/V ratio. [less ▲]

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