References of "Blecker, Christophe"
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See detailCharacterisation of proteins from date palm sap (Phoenix dactylifera L.) by a proteomic approach
Ben Thabet, Imène; Francis, Frédéric; De Pauw, Edwin et al

in Food Chemistry (2010)

The proteins contained in juice tapped from date palm (Phoenix dactylifera L.), from Deglet Nour variety, were analysed by the application of two-dimensional electrophoresis (2DE). Identification was ... [more ▼]

The proteins contained in juice tapped from date palm (Phoenix dactylifera L.), from Deglet Nour variety, were analysed by the application of two-dimensional electrophoresis (2DE). Identification was carried out by mass spectrometry analyses. The SDS–PAGE patterns showed more than 100 spots of which 52 spots were identified. A proportion of the identified proteins were related to Saccharomyces cerevisiae that may belong to the natural microflora of date palm sap. These proteins are principally involved in glycolysis. While other proteins were assigned to be vegetable proteins, probably a mixture of proteins from the vascular system, which have several biological functions within the palm tree. Thus, we found enzymes involved in stress and defence reactions, in glycolysis, and photosynthesis reactions. Other enzymes are associated with carbohydrates and proteins metabolisms. [less ▲]

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See detailEffect of the addition of deffated date seeds on wheat dough performance and bread quality.
Bouaziz, M. A.; Besbes, Souhail; Blecker, Christophe ULg et al

in Journal of Texture Studies (2010), 41

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See detailPectin extraction from lemon by-product with acidified date juice : effect of extraction conditions on chemical composition of pectin.
Masmoudi, M.; Besbes, Souhail; Chaabouni, M. et al

in Food Science & Technology International (2010), 16(2), 105-114

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties ... [more ▼]

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependant on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation. [less ▲]

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See detailA la rencontre de l'innovation technologique: la valorisation alimentaire
Blecker, Christophe ULg

Scientific conference (2010, March 24)

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See detailImpact of the crystallisation pathway of inulin on its mono-hydrate to hemi-hydrate thermal transition
Ronkart, Sébastien; Deroanne, Claude; Paquot, Michel ULg et al

Poster (2010, March 22)

Inulin plays a major role in the food industry as dietary fibre, bulking agent and fat or sugar substitute. Thermal properties of two inulins obtained from different crystallisation pathways were ... [more ▼]

Inulin plays a major role in the food industry as dietary fibre, bulking agent and fat or sugar substitute. Thermal properties of two inulins obtained from different crystallisation pathways were investigated. The first one, was obtained by fractional precipitation of a saturated inulin solution (40/120). The second one, came from a solid amorphous inulin (95/120). These two inulins were spray dried with an inlet air temperature of 120°C. Then, these powders were placed into controlled atmosphere conditions at 0 % HR during one week and at 94% during the same time. Finally the two inulins were called 40/120/94% and 95/120/94% and their thermal properties were investigated by Wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), temperature resolved wide angle X-ray scattering (TRWAXS) and thermogravimetry (TGA).Although WAXS did not show any difference between the two inulin, thermal analysis revealed the existence of a hemi-hydratate inulin (40/120/94%). This fact has an implication on the processing of the powder at an industrial level. Indeed, 40/120/94% has shown an agglomeration whereas 95/120/94% was a continuous mass. In other words, polymorphism of inulin crystals induces technofunctionality changes of the powder (hygroscopy, solubility, etc.) which could have an impact during processing or formulation of the powder. [less ▲]

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See detailScreening of basic properties of amphiphilic molecular structures for colloidal system formation and stability: case of carbohydrate-based surfactants
Razafindralambo, Hary ULg; Blecker, Christophe ULg; Paquot, Michel ULg

Conference (2010, March 21)

Carbohydrate-based surfactants (CBS) are amphiphilic molecules with particular interests. These surface-active compounds can be produced from the most abundant renewable materials allowing large product ... [more ▼]

Carbohydrate-based surfactants (CBS) are amphiphilic molecules with particular interests. These surface-active compounds can be produced from the most abundant renewable materials allowing large product concept possibilities. They may occur in a wide range thanks to numerous functional groups. These make possible the design of a quasi-unlimited compounds by (bio)-synthesis of new structures, or by modifying existing natural molecules. This structural diversity can generate a wide range of properties which could be developed in food and non-food applications. Our challenge is to find out the most suitable molecular structures for post)development of CBS according to the specific required properties in various industrial applications. This consists of assessing the interfacial properties of various CBS prepared by chemical, enzymatic, or chemo-enzymatic synthesis routes from the derivatives of bio-renewable materials.The effect of the polar head group, the hydrophobic chains (length, number), and the linker will be presented and discussed. [less ▲]

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See detailMILK INGREDIENT ENRICHED IN POLAR LIPIDS AND USES THEREOF
Dalemans, Daniel; Blecker, Christophe ULg; Bodson, Pascal et al

Patent (2010)

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

Poster (2010, February 16)

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See detailPretreatments and enzymatic hydrolysis of Miscanthus x giganteus for oligosaccharides production: delignification degree and characterisation of the hydrolysis products
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Blecker, Christophe ULg et al

Poster (2010, February 04)

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose ... [more ▼]

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose and other oligosaccharides after enzymatic hydrolysis. Oligosaccharides have recently gotten attention for their health benefits. Two methods were compared in order to quantify lignin: the acid detergent lignin method (procedure of Van Soest most commonly employed by animal scientist and agronomists for analysis of forages) and the Klason lignin procedure. Lignin concentrations in raw material determined by both methods were different; Klason lignin value (23.5%) was greater than the acid detergent lignin concentration (12.9%). Possible reasons of these results will be discussed. Pretreatment by the formic/acid mixture showed a better deliginification rate compared to the soaking in aqueous ammonia method. Results were based on Klason lignin. Analysis of the structural carbohydrates revealed that untreated miscanthus was mainly composed of glucose and xylose. Extracted pulps by both delignification methods were hydrolysed by commercial cellulases and hemicellulases. A major challenge is the characterisation of complex mixtures of lignocellulosic hydrolysates. In this study, the hydrolysis products were separated and quantified by highperformance anion exchange chromatography with pulsed amperometric detection (HPAECPAD). This method was successfully applied to the quantitative analysis of monosaccharides (glucose and xylose) and disaccharides (cellobiose and xylobiose) formed by the enzymatic hydrolysis of pretreated miscanthus. The influence of the pretreatments on the oligosaccharides yields will be presented. [less ▲]

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See detailOSMOTIC DEHYDRATION OF POMEGRANATE SEEDS (PUNICA GRANATUM L.): EFFECT OF FREEZING PRE-TREATMENT
Bchir, Brahim ULg; Souhail, Besbes; Attia, Hamadi et al

in Journal of Food Process Engineering (2010)

The osmotic dehydration of pomegranate seeds was compared using fresh and frozen seeds. The process was carried out at 50C in a 55°Brix solution of sucrose. Freezing pomegranate seeds before osmotic ... [more ▼]

The osmotic dehydration of pomegranate seeds was compared using fresh and frozen seeds. The process was carried out at 50C in a 55°Brix solution of sucrose. Freezing pomegranate seeds before osmotic dehydration involved an increase of effective diffusivity and a reduction in dehydration time. The most significant changes of water loss (WL) (46 g/100 g of fresh seeds [FS]) and solids gain (SG) (7 g/100 g of FS) took place during the first 20 min for frozen seeds. After this period, seeds WL and SG ranged on average close to 43 and 8 g/100 g of FS, respectively. Osmotic dehydration was slower starting from fresh fruits but led to a higher rate of WL (62 g/100 g of FS) at the end of the process. Both scanning electron microscopy and texture analysis showed a destruction of cell structure and seed texture during the pretreatment (freezing). The same techniques also revealed a texture/structure modification induced by the osmotic dehydration process [less ▲]

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See detailAnalysis of aldehydes relaesed by rice flour using sorbent adsorption and thermal desorption - gas chromatography/mass spectrometry: Development and validation
Mertens, Cécile ULg; Marlet, Christelle ULg; Blecker, Christophe ULg et al

Poster (2010, January)

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the ... [more ▼]

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the presence of three aldehydes: Hexanal, Octanal, Nonanal. These compounds are known to be caused by lipid oxidation, one of the major alteration reactions in food. The Method was developed and valited on a large range for the three aldehydes. It was then applied to the rice fllour to determine if it can be used to follow the effect of ageing on the aldehydes production. [less ▲]

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See detailA multistage process to enhance cellobiose production from cellulosic materials
Vanderghem, Caroline ULg; Boquel, Pascal; Blecker, Christophe ULg et al

in Applied Biochemistry and Biotechnology (2010), 160(8), 2300-2307

Cellobiose, a disaccharide, is a valuable product that can be obtained from cellulose hydrolysis. In this study, a simple methodology is presented to enhance the production and improve the selectivity of ... [more ▼]

Cellobiose, a disaccharide, is a valuable product that can be obtained from cellulose hydrolysis. In this study, a simple methodology is presented to enhance the production and improve the selectivity of cellobiose during enzymatic hydrolysis of cellulose. The approach consisted of a multistage removal of filtrate via vacuum filtration and resuspension of the retentate. By this process, the remaining solid was further hydrolyzed without additional enzyme loading. Compared to the continuous hydrolysis process, the production of cellobiose increased by 45%. Increased selectivity of cellobiose is due to the loss of beta-glucosidases in the filtrate, while enhanced productivity is likely due to mitigated product inhibition. [less ▲]

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See detailFluorescence spectroscopy coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems.
Hammami, M.; Rouissi, H.; Salah, N. et al

in Food Chemistry (2010)

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See detailMilk fat globule membrane and buttermilks: from composition to valorization
Vanderghem, Caroline ULg; Bodson, Pascal; Danthine, Sabine ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(3), 485-500

Buttermilk, the by-product from butter manufacture, is low cost and available in large quantities but has been considered for many years as invaluable. However, over the last two decades it has gained ... [more ▼]

Buttermilk, the by-product from butter manufacture, is low cost and available in large quantities but has been considered for many years as invaluable. However, over the last two decades it has gained considerable attention due to its specific composition in proteins and polar lipids from the milk fat globule membrane (MFGM). The aim of this review is to take stock of current buttermilk knowledge. Firstly, the milk fat globule membrane composition and structure are described. Secondly, buttermilk and its associated products are defined according to the milk fat making process. Structure and mean composition of these products are summarized from recent dairy research data and related to technological properties, especially the emulsifying properties provided by MFGM components. Finally, new applications are presented, leading to promising valorizations of buttermilk and its derivate products. [less ▲]

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See detailLa steam explosion : application en tant que prétraitement de la matière cellulosique
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Blecker, Christophe ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(Spécial N°2),

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 cristallinity 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 or high value-added molecules process. [less ▲]

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See detailImpact of the crystallisation pathway of inulin on its mono-hydrate to hemi-hydrate thermal transition
Ronkart, S. N.; Deroanne, C.; Paquot, Michel ULg et al

in Food Chemistry (2010), 119(1), 317-322

In this paper, we present the thermal properties of two inulins obtained from different crystallisation pathways. One was obtained by fractional precipitation of a saturated inulin solution and the second ... [more ▼]

In this paper, we present the thermal properties of two inulins obtained from different crystallisation pathways. One was obtained by fractional precipitation of a saturated inulin solution and the second was from the crystallisation of a solid amorphous mulin. The thermal analyses were conducted by temperature resolved wide angle X-ray scattering (TRWAXS), differential scanning calorimetry (DSC) and thermogravimetry (TG). Although at room temperature both inulins presented similar X-ray diffractogram patterns characteristic of the mono-hydrate polymorph, they differed considerably by their thermal properties. During heating, a difference in the mono-hydrate to the hemi-hydrate polymorph transition occurred. Thermogravimetric analysis suggested a difference in the water mobility inside the material which had an impact on the thermal properties and hydrate transition of the crystalline inulin. (C) 2009 Elsevier Ltd. All rights reserved. [less ▲]

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See detailComparison of the glucooligosaccharide profiles produced from maltose by two different transglucosidases from Aspergillus niger
Goffin, Dorothée ULg; Wathelet, Bernard ULg; Blecker, Christophe ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010)

Prebiotic isomaltooligosaccharide preparations contain α-D-glucooligosaccharides and their structure is the key factor for their prebiotic potential. The transglucosylation selectivity is known to depend ... [more ▼]

Prebiotic isomaltooligosaccharide preparations contain α-D-glucooligosaccharides and their structure is the key factor for their prebiotic potential. The transglucosylation selectivity is known to depend on the enzyme specificity and moreover, maltose and -glucooligosaccharides can actually act as both glucosyl donor and acceptor in the reaction. Thus, two commercial enzymes, a glycosyl-tranferase and an -glucosidase, were tested alone and in combination on pure maltose to study their specificities and the IMO profile obtained. The reactions were monitored using a step-forward AEC-PAD analytical method which permitted to detect and resolve new unknown IMO. Structural determination of unknown IMO was attempt using their retention times and relative abundance. As a general rule, the -glucosidase has a more expressed hydrolyzing activity leading to products containing less residual digestible -(1-4) linkages such as isomaltose, isomaltotriose, isomaltotetraose, kojibiose and nigerose while the glucosyl-transferase produces important amount of panose. Finally, the combination of the two enzymes leaded to an intermediate IMO profile. IMO syrups composition was thus proved to be dependant on the specificity of the transglucosylating enzyme so that products profiles can be designed using different enzymes and in different proportion. [less ▲]

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See detailOptimisation of xanthan gum production by palm date (Phoenix dactylifera L.) juice by-products using response surface methodology
Ben Salah, Riadh; Chaari, Kacem; Besbes, Souhail et al

in Food Chemistry (2010), 121(2), 627-633

The present study was undertaken investigate and optimise the possibility of xanthan gum production by Xanthomonas campestris NRRL B-1459 in batch experiments on date palm juice by-products. Using an ... [more ▼]

The present study was undertaken investigate and optimise the possibility of xanthan gum production by Xanthomonas campestris NRRL B-1459 in batch experiments on date palm juice by-products. Using an experimental Response Surface Methodology complemented with a Central Composite Orthogonal Design, three major independent variables (date juice carbon source, nitrogen source and temperature) were evaluated for their individual and interactive effects on biomass and xanthan gum production. The optimal conditions selected were: 84.68 g/l for carbon source, 2.7 g/l for nitrogen source, and 30.1 degrees C for temperature. The experimental value obtained for xanthan production under these conditions was about 43.35 g/l, which was close to the 42.96 g/l value predicted by the model. Higher yields of biomass production could be obtained at 46.68 g/l for carbon source, 4.58 g/l for nitrogen source and 30 degrees C for temperature. The maximum value obtained for biomass production was 3.35 g/l, which was higher than the 2.98 g/l value predicted by the model. The xanthan formed was subjected to HPLC and TLC analyses and its molecular weight as well as pyruvate content were identified. The findings indicated that this polysaccharide contained glucose, glucoronic acid and mannose. Overall, the date palm juice by-products presented in the current study seem to exhibit promising properties that can open new pathways for the production of efficient and cost-effective xanthan gum. (C) 2010 Elsevier Ltd. All rights reserved. [less ▲]

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See detailRheological and physical properties of date juice palm by-product (phoenix dactylifera L.) and commercial xanthan gums.
Ben Salah, Riadh; Besbes, Souhail; Chaari, Kacem et al

in Journal of Texture Studies (2010), 41(2), 125-138

Rheological and thermal properties of xanthan produced by Xanthomonas campestris from date by-products (DBP-xanthan) and commercial xanthan were determined. DBP-xanthan gave solutions with lower apparent ... [more ▼]

Rheological and thermal properties of xanthan produced by Xanthomonas campestris from date by-products (DBP-xanthan) and commercial xanthan were determined. DBP-xanthan gave solutions with lower apparent viscosity than commercial xanthan. However, DBP-xanthan solutions were more stable to temperature changes and ionic strength than commercial xanthan. Gradual increase of storage modulus (G') as function of frequency was observed for the two polysaccharides. On the other hand, loss modulus (G ') remained constant for DBP-xanthan and an increase was observed for commercial xanthan. Granulometric profile indicates that DPB-xanthan particle size was lower than commercial xanthan. Differential scanning calorimetry showed that the melting temperatures (T-m) and enthalpy (Delta H-m) of DBP-xanthan were higher than those of commercial xanthan. These properties of DBP-xanthan are quite rare among xanthan described in the literature and give this new gum great potential for use in the field of bioindustries as thickening and stabilizing agents. PRACTICAL APPLICATIONS Xanthan gum from date by-products (DBP-xanthan) was recently produced in our laboratory. No work has been undertaken to study the rheological properties of this polysaccharide to date. Rheological and some physicals properties were compared to those of commercial xanthan. This could promote industrial use of DBPs as low-cost natural source for xanthan gum production. [less ▲]

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