References of "Blecker, Christophe"
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See detailPreparation and characterization of osmodehydrated fruit from lemon and date by-products.
Masmoudi, M.; Besbes, Souhail; Blecker, Christophe ULg et al

Poster (2006, May)

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See detailComposition chimique des graines de pin d'Alep (Pinus halepensis Mill.) d'origine tunisienne et caracterisation de la fraction lipidique.
Cheikh Rouhou, S.; Hentati, B.; Besbes, Souhail et al

Poster (2006, May)

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See detailNigella sativa L. : Chemical composition and characteristics of its lipid fraction.
Cheikh Rouhou, S.; Besbes, Souhail; Hentati, B. et al

Poster (2006, March)

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See detailTotal water determination in inulin using the volumetric Karl Fischer titration and external water extraction in formamide.
Ronkart, Sébastien; Paquot, Michel ULg; Fougnies, C. et al

Poster (2006, March)

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See detailCaking phenomena and physical parameters of amorphous inulin related to adsorption and desorption isotherms.
Ronkart, Sébastien; Paquot, Michel ULg; Fougnies et al

Poster (2006, March)

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See detailDetermination of physical changes of inulin related to sorption isotherms: An X-ray diffraction, modulated differential scanning calorimetry and environmental scanning electron microscopy study
Ronkart, Sébastien ULg; Blecker, Christophe ULg; Fougnies, C. et al

in Carbohydrate Polymers (2006), 63(2), 210-217

This paper gives a relationship between powdered inulin behaviour and physical parameters determination. Glass transition temperature (T,) and development of crystallinity were measured in relation to the ... [more ▼]

This paper gives a relationship between powdered inulin behaviour and physical parameters determination. Glass transition temperature (T,) and development of crystallinity were measured in relation to the water moisture of the polymer. These parameters were obtained by Modulated Differential Scanning Calorimetry (MDSC) and powder X-ray diffraction, respectively. In order to change the water content of the powder, adsorption and desorption isotherms (using different relative humidity storage conditions) were done and successfully fitted to the Guggenheim-Anderson-de Boer (GAB) model. Dependent on the relative humidity storage, a caking phenomenon occurred when glass transition temperature was under storage temperature. An Environmental Scanning Electron Microscopy (ESEM) study showed a structural change when water activity increased above 0.56 at 20 degrees C. A correlation between the increase of the crystallinity and the hardening of the powder was determined. ESEM permitted an observation of the development of some crystal structures among the amorphous system, confirmed by an increase of the diffraction peaks obtained by powder X-ray diffraction. These observations lead to an understanding of the physical characteristics of inulin related to the water moisture. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailVoies de valorisation des pulpes de dattes.
Besbes, Souhail; Cheikh-Rouhou, S.; Blecker, Christophe ULg et al

in Microbiol. Hyg. Alim. (2006), 18(52), 8-15

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See detailDetermination of total water content in inulin using the volumetric Karl Fischer titration
Ronkart, S. N.; Paquot, Michel ULg; Fougnies, C. et al

in Talanta (2006), 70(5), 1006-1010

A new sample preparation method for the water content determination of mulin by volumetric Karl Fischer (KF) titration was developed and compared to the usual method of introducing the sample directly in ... [more ▼]

A new sample preparation method for the water content determination of mulin by volumetric Karl Fischer (KF) titration was developed and compared to the usual method of introducing the sample directly in the methanol-based working medium, modified or not by formamide (1:3, v/v) in order to increase sample solubility. In the proposed method, inulins were externally prepared by dissolving them in pure formamide (2.5:7.5, w/w). The time of analysis of the liquid/liquid reaction of the new method between the dissolved sample and the reaction medium is about 1-2 min, while the usual KF method is stopped after the 10 min delay time. The developed method permits the determination of water included in the crystals of the sample, confirmed by analysing both crystalline and amorphous mulin samples. Another advantage of this new method is its applicability for the water content determination of other polysaccharides that are not readily soluble in the working medium. Moreover. water content determination can be done by any type of volumetric KF titrator, as this proposed technique is not dependent on any additional tools such as a built-in homogeniser or a heatable titration beaker. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailEssai de valorisation d'écarts de triage de dattes : élaboration et caractérisation d'un extrait concentré de la pulpe.
Cheikh-Rouhou, S.; Ben Amara, W.; Besbes, Souhail et al

in Microbiol. Hyg. Alim. (2006), 18(51), 3-12

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See detailElaboration d'une boisson de dattes clarifiée par traitement enzymatique et par filtration membranaire : étude des propriétés d'écoulement.
Cheick-Rouhou, S.; Baklouti, S.; Hadj-Taïeb, N. et al

in Fruits (2006), 61

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See detailContribution to the study of camel milk fat globule membrane
Karray, Nadia Laadhar; Danthine, Sabine ULg; Blecker, Christophe ULg et al

in International Journal of Food Sciences & Nutrition (2006), 57(5-6), 382-390

The camel milk fat globule membrane has been characterized according to several approaches. Compared with the cow milk fat globule membrane, various specificities have been revealed. Its physicochemical ... [more ▼]

The camel milk fat globule membrane has been characterized according to several approaches. Compared with the cow milk fat globule membrane, various specificities have been revealed. Its physicochemical composition showed a poor content in proteins, and a higher content in neutral lipids and in phospholipids. The mechanical properties measured at low (4 degrees C, 20 degrees C) and high temperatures (40 degrees C, 45 degrees C and 50 degrees C) using a film balance are different when the camel milk fat globule membrane is spread at the air-water interface. The thermal study revealed an important proportion of high-melting triacylglycerols that involves fatty acids with long chains. [less ▲]

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See detailChemical composition and lipid fraction characteristics of aleppo pine (Pinus halepensis Mill.) seeds cultivated in Tunisia
Cheikh-Rouhou, S.; Hentati, B.; Besbes, S. et al

in Food Science & Technology International (2006), 12(5), 407-415

The proximate composition of Aleppo pine (Pinus halepensis Mill.) seeds cultivated in Bizerta (Tunisia) were investigated for their fatty acid composition, and their thermal and physical properties of ... [more ▼]

The proximate composition of Aleppo pine (Pinus halepensis Mill.) seeds cultivated in Bizerta (Tunisia) were investigated for their fatty acid composition, and their thermal and physical properties of lipid fraction. The proximate analysis of pine seeds showed the following composition (on a dry-weight basis): protein 22.7%, oil 43.3%, ash 8.3% and total carbohydrate 25.7%. Potassium, magnesium and calcium were the predominant mineral elements present in the seeds and reached, together, about 1%. Oleic and linoleic acids were the major unsaturated fatty acids (27.3 and 48.8%, respectively), while the main saturated one was palmitic acid (8.75%). Myristic, myristoleic, palmitoleic, margaric, margaroleic, stearic, linolenic, arachidic, eicosenoic, eicosadienoic eicosatrienoic behenic and lignoceric acids were also detected. Thermal profile of Pinus halepensis Mill. seed oil, determined by its DSC melting curve, showed that the entire liquefaction of the Aleppo pine seed oil occurs at -8 degrees C. GeLab colour parameters (L*, a*, b*), oxidative stability by Rancimat test and viscosity were also determined. Physicochemical properties of the oil include: saponification number 190, peroxide value 3.18, iodine index 117, and a low acidity of 0.61%. Results suggested that the production of oil from Pinus halepensis seeds could provide a potential use in food, pharmaceutical, cosmetics and other non-food industries. [less ▲]

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See detailStrategy for the qualitative and quantitative analysis of crop syrup containing enzymatically produced Isomaltooligosaccharides known as emerging prebiotics.
Goffin, Dorothée ULg; Blecker, Christophe ULg; Wathelet, Bernard ULg et al

Poster (2006)

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human ... [more ▼]

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human subjects, support the involvement of dietary oligosaccharides in physiological processes in the different intestinal cell type and also outside the gastrointestinal tract (e.g. hormone production, lipid and carbohydrate metabolism). IMOs consists of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose family) glucosidic linkages. In our case they are produced enzymatically from corn starch. It results in a very complex mixture with molecules characterized at the same time by their DP value (from 2 to ~20), linkages types (α-1-2, 3 or 6) and the proportion and position of each type of linkage (only α -1-6 or combined types). The challenge of this study was to find a qualitative and quantitative method to characterize the syrups. In a subsequent study, every unidentified peak could be determined by NMR or Mass spectrometry. Three different chromatographic methods have been tested and compared over their selectivity, sensibility, robustness, applicability and their quantitative power. The HPLC-RID (Refractive Index Detector) used with a Prevail Carbohydrate column (Alltech), adapted for carbohydrates with a certain value of DP, appear to be poorly selective due to the obligation of working in isocratic conditions. The HPLC-ELSD (Evaporating Light Scattering Detector) used with the same column gave a very good separation upon the DP as the Prevail accepts a wide range of solvant changing and even a separation of the different DP 2 molecules. The sensibility was also improved due to the stability of the baseline. The quantitative analysis is a bit more awkward due to the relatively limited linear portion of the calibration curve. High-performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection (HPAEC-PAD) appeared to deserve a special mention, since it provides selective separation and sensitive detection. In fact, this technique is the only chromatographic one to separate with effectiveness homologue molecules having a difference only in their DP (up to high DPs) or linkage types. This is due to the separation mode based on the difference in ionic force of the sugars in alkaline conditions (mainly due to the DP and the structure of the molecule). However, during the detection, the electrochemical behavior of carbohydrates can be affected by molecular weight as well as by structural differences giving rise to different response factors; as a consequence, HPAEC-PAD is not generally considered as suitable for quantitative studies of complex mixtures of oligosaccharides. In this work a methodological approach is presented in order to get a quantitative response through a rigorous methodology for our IMOs. It also opens the way to the theoretical determination of the response factor for the homologue molecules in relation with their structure and DP. [less ▲]

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See detailStrategy for the qualitative and quantitative analysis of crop syrup containing enzymatically produced Isomaltooligosaccharides known as emerging prebiotics
Goffin, Dorothée ULg; Blecker, Christophe ULg; Wathelet, Bernard ULg et al

Poster (2006)

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human ... [more ▼]

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human subjects, support the involvement of dietary oligosaccharides in physiological processes in the different intestinal cell type and also outside the gastrointestinal tract (e.g. hormone production, lipid and carbohydrate metabolism). IMOs consists of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose family) glucosidic linkages. In our case they are produced enzymatically from corn starch. It results in a very complex mixture with molecules characterized at the same time by their DP value (from 2 to ~20), linkages types (α-1-2, 3 or 6) and the proportion and position of each type of linkage (only α -1-6 or combined types). The challenge of this study was to find a qualitative and quantitative method to characterize the syrups. In a subsequent study, every unidentified peak could be determined by NMR or Mass spectrometry. Three different chromatographic methods have been tested and compared over their selectivity, sensibility, robustness, applicability and their quantitative power. The HPLC-RID (Refractive Index Detector) used with a Prevail Carbohydrate column (Alltech), adapted for carbohydrates with a certain value of DP, appear to be poorly selective due to the obligation of working in isocratic conditions. The HPLC-ELSD (Evaporating Light Scattering Detector) used with the same column gave a very good separation upon the DP as the Prevail accepts a wide range of solvant changing and even a separation of the different DP 2 molecules. The sensibility was also improved due to the stability of the baseline. The quantitative analysis is a bit more awkward due to the relatively limited linear portion of the calibration curve. High-performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection (HPAEC-PAD) appeared to deserve a special mention, since it provides selective separation and sensitive detection. In fact, this technique is the only chromatographic one to separate with effectiveness homologue molecules having a difference only in their DP (up to high DPs) or linkage types. This is due to the separation mode based on the difference in ionic force of the sugars in alkaline conditions (mainly due to the DP and the structure of the molecule). However, during the detection, the electrochemical behavior of carbohydrates can be affected by molecular weight as well as by structural differences giving rise to different response factors; as a consequence, HPAEC-PAD is not generally considered as suitable for quantitative studies of complex mixtures of oligosaccharides. In this work a methodological approach is presented in order to get a quantitative response through a rigorous methodology for our IMOs. It also opens the way to the theoretical determination of the response factor for the homologue molecules in relation with their structure and DP. [less ▲]

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See detailDéfense végétale, biotechnologies et développement de bio-insecticides
Francis, Frédéric ULg; Blecker, Christophe ULg; Deroanne, Claude et al

in Abstract book (2006)

Detailed reference viewed: 17 (2 ULg)
See detailSynthese enzymatique d’esters de sucre au départ d’huiles végétales
Detry, J.; Destain, Jacqueline ULg; Lognay, Georges ULg et al

Poster (2005, October 14)

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See detailSugar esters lipase mediated synthesis from vegetable oils
Destain, Jacqueline ULg; Detry, Jean; Lognay, Georges ULg et al

Scientific conference (2005, September 19)

Detailed reference viewed: 32 (3 ULg)
See detailSugar esters lipase mediated synthesis from vegetable oils
Destain, Jacqueline ULg; Detry, J.; Lognay, Georges ULg et al

Poster (2005, September)

Detailed reference viewed: 24 (5 ULg)