References of "Paquot, Michel"
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See detailEnzymatic production of pectic oligosaccharides from polygalacturonic acid with commercial pectinase preparations
Combo, Agnan Marie Michel ULg; Aguedo, Mario ULg; Goffin, Dorothée ULg et al

in Food and Bioproducts Processing: Transactions of the Institution of Chemical Engineers, Part C (2011), 90(3), 588-596

The present study investigates the individual efficiency of six commercial pectinase preparations (Endopolygalacturonase M2, Pectinase, Viscozyme L, Pectinex Ultra SP-L, Pectinase 62L and Macer8 FJ) in ... [more ▼]

The present study investigates the individual efficiency of six commercial pectinase preparations (Endopolygalacturonase M2, Pectinase, Viscozyme L, Pectinex Ultra SP-L, Pectinase 62L and Macer8 FJ) in catalyzing the liberation of pectic oligosaccharides (POS) from polygalacturonic acid. On the basis of high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) analysis of the enzymatic hydrolysates, products release kinetics revealed a random cleavage pattern and an exo mode of cleavage for all the enzymes except for Endopolygalacturonase M2. All six enzymes generated oligoGalA with different degree of polymerization (DP); the quantitative composition of oligoGalA depended on the enzyme specificity and the time of enzymatic reaction. Endopolygalacturonase M2 was the best enzyme preparation for production of oligoGalA, with 18% (wt) of digalacturonic acid and 58% (wt) of trigalacturonic acid after 2h of reaction. Concerning galacturonic acid production, Pectinase 62L was superior to the other enzyme preparations with 47% (wt) after 1h of reaction. [less ▲]

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See detailPenetration behaviour of alkylbetainate chlorides into lipid monolayers
Nsimba Zakanda, Francis ULg; Nott, Katherine ULg; Paquot, Michel ULg et al

in Colloids and Surfaces B : Biointerfaces (2011), 86

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See detailAlkylbetainate chlorides: Synthesis and behavior of monolayers at the air-water interface
Nsimba Zakanda, Francis ULg; Laurent, Pascal ULg; Paquot, Michel ULg et al

in Thin Solid Films (2011), 520

In this study, cationic alkylbetainate chloride surfactants (CnBC, n = 10–16) are synthesized using more environment-friendly reagents (glycine betaine, thionyl chloride and primary alcohols) than in ... [more ▼]

In this study, cationic alkylbetainate chloride surfactants (CnBC, n = 10–16) are synthesized using more environment-friendly reagents (glycine betaine, thionyl chloride and primary alcohols) than in previous works (chloroacetyl chloride, trimethylamine and primary alcohols). The interfacial behavior of the CnBC monolayers is studied onto aqueous subphases at 20 °C using the Langmuir through technique. Different experimental conditions including pH, temperature, sodium salts and Na2SO4 ionic strength are investigated. The results obtained have shown that the CnBC with a hydrocarbon chain length ≥ 14 are able to form insoluble monolayers. The C16BC monolayer stability checked by the compression–expansion cycles has shown a superimposition of isotherms in the whole liquid-condensed region and an irreversible rearrangement of the molecules at high compression. The C16BC monolayer is not influenced by the pH and the presence of monovalent anions but it is influenced by the temperature, the divalent anions and the ionic strength. It has exhibited a great stability whatever the experimental conditions. [less ▲]

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See detailRipening influences banana and plantain peels composition and energy content
Happi Emaga, Thomas ULg; Bindelle, Jérôme ULg; Angeesens, Richard et al

in Tropical Animal Health and Production (2011), 43

Musa sp. peels are widely used by smallholders as complementary feeds for cattle in the tropics. A study of the influence of the variety and the maturation stage of the fruit on fermentability and ... [more ▼]

Musa sp. peels are widely used by smallholders as complementary feeds for cattle in the tropics. A study of the influence of the variety and the maturation stage of the fruit on fermentability and metabolisable energy (ME) content of the peels was performed using banana (Yangambi Km5) and plantain (Big Ebanga) peels at three stages of maturation in an in vitro model of the rumen. Peel samples were analysed for starch, free sugars and fibre composition. Samples were incubated in the presence of rumen fluid. Kinetics of gas production were modelled, ME content was calculated using prediction equation and short-chain fatty acids production and molar ratio were measured after 72 h of fermentation. Final gas production was higher in plantain (269–339 ml g−1) compared to banana (237–328 ml g−1) and plantain exhibited higher ME contents (8.9–9.7 MJ/kg of dry matter, DM) compared to banana (7.7–8.8 MJ/kg of DM). Butyrate molar ratio decreased with maturity of the peels. The main influence of the variety and the stage of maturation on all fermentation parameters as well as ME contents of the peels was correlated to changes in the carbohydrate fraction of the peels, including starch and fibre. [less ▲]

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See detailWill isomalto-oligosaccharides, a well-established functional food in Asia, break through the European and American market? The status of knowledge on these prebiotics
Goffin, Dorothée ULg; Delzenne, Nathalie; Blecker, Christophe ULg et al

in Critical Reviews in Food Science & Nutrition (2011)

This critical review article present the current state of knowledge on isomaltooligosaccharides, some well known functional oligosaccharides in Asia, to evaluate their potential as emergent prebiotics in ... [more ▼]

This critical review article present the current state of knowledge on isomaltooligosaccharides, some well known functional oligosaccharides in Asia, to evaluate their potential as emergent prebiotics in the American and European functional food market. It includes first a unique inventory of the different families of compounds which have been considered as IMO and their specific structure. A description of the different production methods including the involved enzymes and their specific activities, the substrates and the types of IMO produced. Considering the structural complexity of IMO products, specific characterization methods are described as well as purification methods which enable the riddance of digestible oligosaccharides. Finally an extensive review of their techno-functional and nutritional properties enables to place IMO inside the growing prebiotic market. This review is of a particular interest considering that IMO commercialization in America and Europe is a topical subject due to the recent submission, by Bioneutra INC. (Canada), of a novel food file to the UK Food Standards Agency as well as several patents for IMO production. [less ▲]

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See detailEffect of drying methods on physico-chemical and antioxidant properties of date fibre concentrates
Borchani, I.; Besbes, S.; Masmoudi, M. et al

in Food Chemistry (2011), 125

Effects of different drying methods (freeze-, oven- and sun-drying) on physico-chemical properties of date fibre concentrates (DFC) from three potential Tunisian cultivars were investigated. DFC had high ... [more ▼]

Effects of different drying methods (freeze-, oven- and sun-drying) on physico-chemical properties of date fibre concentrates (DFC) from three potential Tunisian cultivars were investigated. DFC had high contents of dietary fibre (71.01–93.46% dry matter), with high proportions of insoluble dietary fibre. Freeze dried DFC had the highest values of swelling, water holding and oil holding capacities. This drying method gave also the lightest DFC colour. Kentichi fibre produced by freeze-drying had the highest viscosity and the lowest bulkier particles. The present work assessed polyphenol content and antioxidant activity of DFC using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The highest polyphenol content was found for freeze dried DFC, contrary to radical scavenging activity which was not affected by drying methods. Results suggest that freeze dried DFC had the highest potential to be used as a functional ingredient in food products. [less ▲]

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See detailSynthesis and physico-chemical characterization of bolaamphiphiles derived from alkenyl D-xylosides
Deleu, Magali ULg; Damez, Céline; Gatard, Sylvain et al

in New Journal of Chemistry (2011), 35

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See detailFlaxseed proteins: food uses and health benefits flaxseed proteins
Rabetafika, Holy-Nadia ULg; Van Remoortel, Vinciane ULg; Danthine, Sabine ULg et al

in International Journal of Food Science & Technology (2011), 46(2), 221-228

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See detailNew method for the purification of electrically charged polysaccharides
Garna, Haikel; Emaga, Thomas Happi; Robert, Christelle et al

in Food Hydrocolloids (2011), 25(5), 1219-1226

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See detailCharacterization of hemicellulosic fractions from spelt hull extracted by different methods
Escarnot, Emmanuelle; Aguedo, Mario ULg; Paquot, Michel ULg

in Carbohydrate Polymers (2011), 85

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See detailImpact of a formic/acetic acid treatment of beech wood on delignification and chemical structure of lignins
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Conference (2011)

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

Lignocellulosic substrates constitute a promising alternative resource for the sustainable production of energy (biofuels), biobased products and organic compounds. In the past, the extraction and the valorization of cellulose (into fermentescible glucose) constituted the central axis of lignocellulosic biorefinery processes. Degraded hemicelluloses and lignins were however 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 transformation of lignins have opened recently new horizons. Lignin is a cross-linked phenolic polymer and is considered as a 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 is dependent of 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.) collected in the region of Gaume (Belgium) were delignified at atmospheric pressure by a mixture of formic acid/acetic acid/water. The effect of cooking time and temperature was evaluated on delignification and on chemical structure of lignins obtained by precipitation from the black liquor after treatments. To study the delignification, a central composite design and response surface methodology were used for the optimization of two treatments parameters, i.e. time (between 1h30 and 4h30) and temperature (from 87 to 107°C). These two variables were optimized for delignification yield, pulp yield, concentration of degradation products (furfural and hydroxymethylfurfural) and for the amount of residual linkages between lignin constitutive units. On the basis of our results, higher delignification yields were obtained when cooking time and temperature increased. However, for high cooking times and temperatures, pulp yield decreased because hemicelluloses and cellulose were hydrolyzed and the production of furfural and hydroxymethylfurfural was augmented. The structural and physico-chemical features of extracted lignins were investigated with different analytical tools, namely infrared spectrometry, thermogravimetric analysis, size-exclusion chromatography, mono-dimensional nuclear magnetic resonance (NMR 1H and NMR 13C) and bidimensional NMR (heteronuclear HSQC experiments). The characterization of lignins indicated the occurrence of a repolymerization phenomenon when both cooking time and temperature increased. Indeed, HSQC NMR spectra presented oxidized syringyl units. Otherwise, thermogravimetric analysis and HSQC analysis showed the presence of hemicelluloses in lignin samples from soft treatments (1h30, 87°C). Some linkages between lignin and hemicelluloses were not cleaved under these experimental conditions. [less ▲]

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See detailImpact of the treatment conditions of a formic/acetic acid delignification method on chemical structure and antioxidant activity of beech wood lignin
Simon, Mathilde ULg; Vanderghem, Caroline ULg; Richel, Aurore ULg et al

Poster (2011)

The interest in lignocellulosic substrates is increasing because they are clearly identified for their high potential of development in energy and value-added molecules production. Indeed lignocellulosic ... [more ▼]

The interest in lignocellulosic substrates is increasing because they are clearly identified for their high potential of development in energy and value-added molecules production. Indeed lignocellulosic biomass constitutes a promising resource for a sustainable production of organic compounds and biobased products that could progressively replace molecules from the petrochemical industry. Until now lignocellulosic substrates were mainly used for the valorization of cellulose. Hemicelluloses and lignins were less valorized and often degraded after the process. However, due to their phenolic structure, lignins can be valorized in a lot of high-valued applications like vanillin production, replacement of petrochemical polymers, antioxidants for cosmetics and food industry, resins… In this study, a representative sample of beech wood (Fagus sylvatica L.) was collected in the region of Gaume in Belgium. Beech wood was delignified at atmospheric pressure by an organosolv process using a mixture of formic acid/acetic acid/water. The effect of cooking time and temperature was evaluated on the structure, physico-chemical properties and antioxidant activity of the lignins obtained from the black liquor after treatments. The structural and physico-chemical characteristics of the lignins were investigated with different tools like infrared spectrometry, thermogravimetric analysis, gel permeation chromatography after acetylation of lignins, NMR 1H, 13C and HSQC. The antioxidant activity was assessed by a spectrophotometric method using the α,α-diphenyl-β-picrylhydrazyl radical (DPPH). [less ▲]

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See detailOptimization of a formic/acetic acid treatment of beech wood (Fagus sylvatica L.) for delignification
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Poster (2011)

Lignin is a promising molecule constituting a renewable alternative to some petrochemical industry products. Lignin is an aromatic cross-linked heteropolymer composed of three phenylpropanoids (p ... [more ▼]

Lignin is a promising molecule constituting a renewable alternative to some petrochemical industry products. Lignin is an aromatic cross-linked heteropolymer composed of three phenylpropanoids (p-hydroxyphenyl, guaiacyl and syringyl units) linked together via radical coupling reactions by specific ether or carbon-carbon bonds. With this phenylpropanoid structure, lignin is a rich resource of biobased products that could find high-valued applications in a lot of different areas like petrochemical polymer reinforcement and replacement, antioxidants, stabilizers, resins and vanillin production... The first challenge of the valorization of lignins is their extraction from raw materials. Lignins can be found in different lignocellulosic substrates like grasses, softwood and hardwood. This extraction process needs the development of suitable biomass treatments, allowing efficient lignin recuperation without degradation. This one could lead to the loss of some interesting properties and so of some valorization possibilities. In this study, beech wood (Fagus sylvatica L.) was collected in the region of Gaume (Belgium). Beech wood particles were delignified at atmospheric pressure by a mixture of formic acid/acetic acid/water. A central composite design and response surface methodology were used for the optimization of treatment parameters for delignification. The optima of two independent variables, namely time (1h30, 3h, 4h30) and temperature (87°C, 97°C, 107°C), were determined on delignification yield, pulp yield, concentration of degradation products (furfural and hydroxymethylfurfural). Moreover, the impact of these two variables on the amount of residual linkages between phenylpropanoid units was evaluated by semi-quantitative bidimensional nuclear magnetic resonance spectroscopy (NMR-HSQC). Our results highlight that the delignification yields increase when cooking time and temperature are elevated. Nevertheless, under these conditions, pulp yield decreases as hydrolysis of hemicelluloses and cellulose occurs. The hydrolysates of carbohydrates (free sugars or oligosaccharides) are contained in the black liquor. At elevated temperature and time, the amount of degradation products in the black liquor is increased. [less ▲]

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See detailUtilisation des micro-ondes pour la conversion hydrolytique de la biomasse lignocellulosique
Richel, Aurore ULg; Paquot, Michel ULg

in Chimie Nouvelle (2011), 108

The use of microwave is described as a non conventional and original heating source for both pretreatment and hydrolysis of lignocellulosic agroresources into high added value materials. Advantages of ... [more ▼]

The use of microwave is described as a non conventional and original heating source for both pretreatment and hydrolysis of lignocellulosic agroresources into high added value materials. Advantages of this approach are presented in terms of reduced reaction times and improved selectivities and yields. The limitations of this technology are also evaluated. [less ▲]

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See detailEtude des interactions membranaires de dérivés de l’acide glucuronique par calorimétrie à titrage isotherme
Laurent, Pascal ULg; Razafindralambo, Hary ULg; Paquot, Michel ULg

Poster (2011)

Dans le cadre de la valorisation de la biomasse et des glucides provenant de l’hydrolyse de matières premières renouvelables, différents dérivés d’acides uroniques ont été synthétisés en vue d’évaluer ... [more ▼]

Dans le cadre de la valorisation de la biomasse et des glucides provenant de l’hydrolyse de matières premières renouvelables, différents dérivés d’acides uroniques ont été synthétisés en vue d’évaluer leurs propriétés en tant qu’agents tensioactifs biocompatibles et biodégradables. Une nouvelle stratégie de synthèse assistée par micro-ondes, efficace et respectueuse de l'environnement, a par ailleurs permis de synthétiser quantitativement différentes D-glucofuranosidurono-6,3-lactones monosubstituées hydrosolubles au départ d'acide D-glucuronique non protégé en utilisant un catalyseur acide supporté. Ces lactones appartiennent à la famille des glycosurfactants non-ioniques dont les applications couvrent un vaste domaine, aussi bien dans l’industrie pharmaceutique, cosmétique ou alimentaire. Une première approche en vue d’évaluer leurs activités biologiques consiste en l’étude des paramètres d’interactions moléculaires de ces lactones vis-à-vis d’une membrane biologique modèle (1-palmitoyl-2-oleyl-sn-glycerol-3-phosphatidylcholine) par calorimétrie à titrage isotherme (Isothermal Titration Calorimetry – ITC). [less ▲]

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See detailCurrent perspectives on microwave-enhanced reactions of monosaccharides promoted by heterogeneous catalysts.
Richel, Aurore ULg; Laurent, Pascal ULg; Wathelet, Bernard ULg et al

in Catalysis Today (2011), 167

Involvment of heterogeneous catalysts as promoters of carbohydrate conversions, in synergy with microwaves as the heating source, is reported. This paper deals with the application of ion-exchange resins ... [more ▼]

Involvment of heterogeneous catalysts as promoters of carbohydrate conversions, in synergy with microwaves as the heating source, is reported. This paper deals with the application of ion-exchange resins, zeolites, clays and metal oxides as convenient mediators for key transformations of carbohydrates. A special emphasis is placed on the use of (doped) mineral supports, in solventless conditions, as clean promoters in combination with microwave dielectric heating. [less ▲]

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See detailMicrowave-assisted conversion of carbohydrates. State of the art and outlook.
Richel, Aurore ULg; Laurent, Pascal ULg; Wathelet, Bernard ULg et al

in Comptes Rendus Chimie (2011), 14

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast ... [more ▼]

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast, expeditious and cost-effective methodologies for the modification of these naturally occurring compounds is becoming a prerequisite. In this sense, the application of microwaves has gained progressive attention in laboratories for making a range of high-added value sugars derivatives scaffolds. Advantages of microwaves are numerous and include enhancement of reaction rates and yields, combined to improved regio-, chemo- and anomeric selectivities. Summary: 1. Introduction 2. Chemical transformations of monosaccharides Regioselective hydroxyls protections/deprotections Derivatisation at the anomeric position Other derivatisations Microwave-assisted click chemistry Synergy between microwaves and heterogeneous catalysis Enzymatic modifications of monosaccharides 3. Effect of microwave heating on polysaccharides Hydrolysis and pretreatment of cellulose Derivatisation of cellulose 4. Scale-up of microwave-promoted reactions 5. Conclusions [less ▲]

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See detailSynthesis and Surface-Active Properties of Uronic Amide Derivatives, Surfactants from Renewable Organic Raw Materials
Laurent, Pascal ULg; Razafindralambo, Hary ULg; Wathelet, Bernard ULg et al

in Journal of Surfactants and Detergents (2011), 14(1), 51-63

Short chemical syntheses were developed to produce a new set of surfactants from uronic acids derived from widely available raw material. Three different strategies were used to synthesise uronic amide ... [more ▼]

Short chemical syntheses were developed to produce a new set of surfactants from uronic acids derived from widely available raw material. Three different strategies were used to synthesise uronic amide derivatives, the structures of which were totally characterized by spectrometric methods (IR, MS, 1H-RMN and 13C-RMN). The best one, using an acid chloride as synthetic intermediate, furnished the expected amides as a mixture of anomers in 46 to 58 % global yield. Surface-active properties (CMC, g cmc, Tmax, Amin) of homologous series of uronic acid N-alkylamides from C8 to C18 were also assessed. In general, these sugar-based surfactants exhibited good surface-activities, and appeared as valuable non ionic surfactants compared to Triton X-100, the most well-known non ionic surfactant. Increasing the alkyl chain length influenced the CMC values for both glucuronic and galacturonic N-alkylamide derivatives. The galacturonic N-alkylamides decreased g cmc at slower values than their counterpart's glucuronic N-alkylamides. [less ▲]

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See detailEffect of Air-Drying Conditions on Physico-chemical Properties of Osmotically Pre-treated Pomegranate Seeds
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

in Food and Bioprocess Technology (2010)

The drying of pomegranate seeds was investigated <br />at 40 °C, 50 °C and 60 °C with air velocity of 2 m/s. <br />Prior to drying, seeds were osmodehydrated in 55 °Brix <br />sucrose solution for 20 min ... [more ▼]

The drying of pomegranate seeds was investigated <br />at 40 °C, 50 °C and 60 °C with air velocity of 2 m/s. <br />Prior to drying, seeds were osmodehydrated in 55 °Brix <br />sucrose solution for 20 min at 50 °C. The drying kinetics <br />and the effects of osmotic dehydration (OD) and air-drying <br />temperature on antioxidant capacity, total phenolics, colour <br />and texture were determined. Analysis of variance revealed <br />that OD and air-drying temperature have a significant <br />influence on the quality of seeds. Both anthocyanin and <br />total phenolic contents decreased when air-drying temperature <br />increased. The radical diphenylpicril-hydrazyl activity <br />showed the lowest antioxidant activity at 60 °C. Both <br />chromatic parameters (L*, C* and h°) and browning index <br />were affected by drying temperatures, which contributed to <br />the discolouring of seeds. The final product has 22%, 20% <br />and 16% of moisture; 0.630, 0.478 and 0.414 of aw; 151, <br />141 and 134 mg gallic acid equivalent/100 g fresh matter <br />(FM) of total phenolics; 40, 24, 20 mg/100 g FM of <br />anthocyanins and 46%, 39% and 31% of antioxidant <br />activity, for drying temperatures of 40 °C, 50 °C and <br />60 °C, respectively. In view of these results, the temperature <br />of 40 °C is recommended as it has the lowest impact on <br />the quality parameters of the seeds. Differential scanning <br />calorimetry data provided complementary information on <br />the mobility changes of water during drying. Glass <br />transition temperature (Tg′) depends on moisture content <br />and as consequence, on drying conditions. In fact, Tg′ of <br />seeds dried at 60 °C (Tg′=−21 °C) was higher than those <br />dried at 50 °C (Tg′=−28 °C) or 40 °C (Tg′=−31 °C) and <br />osmodehydrated seeds (Tg′=−34 °C). During OD and <br />drying process, the texture of seeds changed. The thickness <br />of seeds shrank by 55% at 60 °C. [less ▲]

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