J.-F. Thibault

French National Institute for Agricultural Research, Lutetia Parisorum, Île-de-France, France

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Publications (137)310.37 Total impact

  • E. Bonnin, M.C. Ralet, J.F. Thibault, H.A. Schols
    Handbook of waste management and co-product recovery in food processing Vol.2, Edited by K. Waldron, 01/2009: pages 257-285; Woodhead Publishing Limited, Cambridge., ISBN: 978-1-84569-391-6
  • Marie-Christine Ralet, J.F. Thibault
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    ABSTRACT: Pectins are extremely complex polysaccharides that can be viewed as multiblock co-biopolymers. Although the fine structure of the different pectic blocks is now quite well known, the way in which they are combined into a macromolecular structure is still a matter of debate. Large differences in pectins quality and quantity exist between different cell types, at different stages of cellular development and even within the thickness of a given wall. A way to understand how the different structural elements are connected to one another to form variable macromolecular structures is to isolate and identify the different connection points. Another, and complementary, way is to specifically isolate the different pectic domains in order to study their hydrodynamic properties. Six monocotyledonous and dicotyledonous species were selected and pectins were extracted from cell wall materials using a four-step sequential extraction scheme. The isolation and characterization of pectin structural elements showed that structural discrepancies of pectins differing in HG/RG-I balance could be due to a variable amount of HG domains decorating an RG-I backbone. Our results also support the hypothesis of a hyper-variability of RG-I backbone length. However, the structural complexity and heterogeneity of pectins make it very difficult to appraise the relationship between pectin fine structure and hydrodynamic properties, especially when the compared pectins are derived from different plant species and obtained with different extractants. The Arabidopsis pectin mutant quasimodo2 was thereby studied. By specifically isolating HG blocks, qua2 appeared to be specifically deficient in HG, with no change in the amount of RG-I blocks. Moreover, the remaining HGs had maintained the same size as those in the wild type. The possible macromolecular build up of pectins is discussed in the light of the presented results.
    Pectins and pectinases, Edited by H.A. Schols, R.G.F. Visser, A.G.J. Voragen, 01/2009: pages 35-48; Wageningen Academic Publishers., ISBN: 978-90-8686-108-8
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    ABSTRACT: An acetylesterase was purified from Aspergillus aculeatus on the basis of its ability to deacetylate homogalacturonan. A series of well-characterized substrates was prepared and used to investigate its specificity, including pectin with various degrees of methylation and acetylation, pectic domains with various structures, and oligomers. It was then compared to a rhamnogalacturonan acetylesterase previously isolated from the same fungus. Both enzymes were active towards various acetylated pectins, and were able to release acetyl groups from acetylated homogalacturonan, oligogalacturonates as well as rhamnogalacturonan at different extent. It was thus concluded that while the two enzymes differed in their efficiency, they are both pectin acetylesterases, able to act in the “smooth” as well as in the “hairy” regions of pectin.
    Carbohydrate Polymers 11/2008; 74(3-74):411-418. DOI:10.1016/j.carbpol.2008.03.014 · 3.92 Impact Factor
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    ABSTRACT: The extraction of pectins from mango peels can offer a way to upgrade byproducts arising from the processing of these tropical fruits. In this work, several extraction conditions (HCl, or deionised water, or ammonium oxalate) were tested in order to isolate pectins from the peels of two mango varieties (Améliorée and Mango) harvested in Cameroon. After determining uronic acid and neutral sugar contents of mango peels and their alcohol insoluble residues (AIR), extracted pectins were analysed for their uronic acid and neutral sugar contents, their degree of methylation and acetylation, and their average molar mass and intrinsic viscosity. The extraction method was shown to significantly act upon yield (9–32% dry AIR), uronic acid (262–709 mg/g dry weight) and neutral sugar (160–480 mg/g) contents of pectin, their degree of methylation (52–86%) and acetylation (1–8%), their molar mass (245,000–432,000 g/mol), and their intrinsic viscosity (320–1346 mL/g). The physicochemical behaviour of pectins could be influenced thereof. With a good recovery yield, a high average molar mass and intrinsic viscosity and a high degree of methylation, ammonium oxalate-extracted mango pectins present good characteristics to be exploited industrially for their gelling properties.
    Food Hydrocolloids 10/2008; DOI:10.1016/j.foodhyd.2007.07.005 · 4.28 Impact Factor
  • Jean‐François Thibault, Marie‐Christine Ralet
    Advanced Dietary Fibre Technology, 04/2008: pages 367 - 378; , ISBN: 9780470999615
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    ABSTRACT: Extraction and use of pectins from ambarella peels could add value to the waste products arising from processing of the fruit. Dried alcohol-insoluble residues (AIR) of ambarella peels were treated separately with HCl, deionised water and oxalic acid/ammonium oxalate solutions, and the resulting pectin extracts analysed for some biochemical and physicochemical parameters. The results show that pectin yield (9–30% dry AIR), uronic acid (557–727 mg/g dry weight), neutral sugars (125–158 mg/g), degree of methylation (50–58%) and acetylation (4–6%), molar mass (263,000–303,000 g/mol) and intrinsic viscosity (179–480 ml/g) varied significantly (p < 0.05) with the various extraction methods used. Extraction with oxalic acid/ammonium oxalate solution gave the highest pectin yield, with high molar mass and degree of methylation, making the extracts suitable for use as additives in the food industry. The results compared well to lime pectin extracted under the same conditions, indicating their commercial significance.
    Food Chemistry 02/2008; 106(3):1202-1207. DOI:10.1016/j.foodchem.2007.07.065 · 3.26 Impact Factor
  • Tree and forestry science and biotechnology 2 Special issue 1, Edited by N. Benkeblia, P. Tennant, 01/2008: pages 60-70; Global Science Books., ISBN: 978-4-903313-17-7
  • M. Panouille, M.C. Ralet, E. Bonnin, J.F. Thibault
    Handbook of waste management and co-product recovery in food processing Vol.1, Edited by K. Waldron, 01/2007: pages 417-447; Woodhead Publishing Limited, Cambridge., ISBN: 978-1-84569-025-0
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    ABSTRACT: The objective of the present work was to relate the physical evolution quantified by image analysis to the chemical transformation of beet pulp particles during enzymatic degradation. Beet pulps were degraded into a torus reactor equipped for visualisation. Pectinolytic and cellulolytic enzymes were used separately or in combination. Two global image analysis techniques were tested to characterise the size distribution of overlapping particles. Granulometric curves were extracted by mathematical morphology and a regularisation dimension was assessed by fractal analysis. Both techniques proved efficient to follow particle size evolution during degradation. When using cellulolytic enzymes alone, no chemical or physical evolution was observed. When using pectinolytic enzymes, a chemical modification occurred without any physical evolution. Particles physically disappeared when both enzymes were used. The chemical and physical evolutions of particles during degradation were interpreted taking into account the current model of molecular arrangement of primary cell walls.
    Journal of Food Engineering 12/2006; DOI:10.1016/j.jfoodeng.2005.08.046 · 2.58 Impact Factor
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    J.-F. Thibault, A. Zykwinska, M. Ralet, C. Garnier
  • Chapter: Pectins
    Polysaccharides and polyamines in the food industry, Edited by A. Steinbüchel, S.K. Rhee, 01/2005: pages 351-387; Wiley-VCH Verlag, Weinheim., ISBN: 3527313451
  • M Thomas, F Guillemin, F Guillon, J.-F Thibault
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    ABSTRACT: The pectin content, composition and physico-chemical properties were studied in the fruits of two genotypes of Japanese quince. On average, the fruits contained 11 g pectins/100 g dry fruit and 1.4 g pectins/100 g fresh fruit. A sequential extraction was used to isolate the pectins from the fruits. The cells from the flesh were examined using a confocal laser scan microscope, fresh and after each extraction step of the sequence. The dilute acid conditions were the most efficient for pectin extraction. Pectins extracted by water or potassium oxalate had higher (>600 ml/g) intrinsic viscosities than the pectins extracted by dilute acid (
    Carbohydrate Polymers 09/2003; 53(4):361-372. DOI:10.1016/S0144-8617(03)00118-8 · 3.92 Impact Factor
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    ABSTRACT: Endopolygalacturonase from Fusarium moniliforme was used to degrade acetylated homogalacturonan previously prepared from sugar beet pulp. The initial velocity and the final percentage of hydrolysis decreased very rapidly with increasing degree of acetylation, showing that acetyl substitution markedly affected the enzymatic activity. MALDI-TOF mass spectrometry was used to analyse the reaction products and to show acetyl groups on the oligogalacturonates. The results demonstrated that the enzyme was able to accommodate acetyl groups in its active site cleft. The influence of acetyl groups on the mode of action of the enzyme was discussed and compared to the influence of methyl groups.
    Carbohydrate Polymers 06/2003; DOI:10.1016/S0144-8617(02)00332-6 · 3.92 Impact Factor
  • Advances in pectin and pectinase research, Edited by A.G.J. Voragen, H.A. Schols, R. Visser, 01/2003: pages 419-430; Kluwer Academic Publishers., ISBN: 1-4020-1144-X
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    ABSTRACT: An improved hplc method for the simultaneous determination of the degrees of methylation and acetylation of pectins has been developed. The proposed method involves saponification in heterogeneous medium followed by the separation of methanol, acetic acid and internal standard on a C18 column and quantification by refractometry. The method is reproducible, accurate, and presents several advantages that are discussed in the present paper.
    Food Hydrocolloids 11/2002; 16(6):547-550. DOI:10.1016/S0268-005X(02)00015-2 · 4.28 Impact Factor
  • K. Rumpunen, M. Thomas, N. Badilas, J.-F. Thibault
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    ABSTRACT: A combined enzymatic and HPLC method was validated for analysis of galacturonic acid (GalA) in (1) alcohol-insoluble solids (AIS), and in (2) pectins, extracted from fruits of Japanese quince (Chaenomeles japonica), by comparison with a standard colorimetric method (using metahydroxydiphenyl) for analysis of uronic acids (UA). For analysis of AIS, the results of the colorimetric and the enzymatic/HPLC methods were identical (UA and GalA in average 20 g/100 g AIS dry weight). For analysis of pectins, the colorimetric method resulted in consistently higher estimates (UA in average 63 g/100 g pectins dry weight) compared to the enzymatic/HPLC method (GalA in average 57 g/100 g pectins dry weight). The enzymatic/HPLC method also proved to be useful as a simple and efficient screening method, since a very high Pearson correlation (R=0.93) was obtained between GalA estimates of the homogenized fruit sample and the AIS content of acid-extracted pectins.
    Lebensmittel-Wissenschaft und-Technologie 09/2002; 35(6-35):490-496. DOI:10.1006/fstl.2002.0895 · 2.47 Impact Factor
  • M Thomas, J.-F Thibault
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    ABSTRACT: The study of the cell-wall polysaccharides of the fruits of Japanese quince (Chaenomeles japonica) was achieved in two stages: (i) preparation of alcohol insoluble solids (AIS) from the different tissue zones and entire fruits of two genotypes and (ii) treatment of the AIS with extractants. The AIS represented an average of 32 g/100 g entire dry fruit and 4 g/100 g entire fresh fruit. A sequential extraction scheme allowed the separation of the cell-wall material into its major components (cellulose, pectins and hemicelluloses). The AIS was composed of 30 g pectins/100 g AIS, 8 g hemicelluloses/100 g AIS and 60 g cellulosic residue/100 g AIS. 100 g entire dry fruit (800 g entire fresh fruit) contained 11 g pectins, 3 g hemicelluloses and 18 g cellulosic residue. Pectins were mostly located in the flesh of the fruit, they were more efficiently extracted with hot dilute acid than with other extraction media and they had a high degree of methylation (DM) and a low degree of acetylation (DAc). Sequential extraction allows a first fractionation of the pectins. Hot dilute acid extracted pectins substituted with long Ara side-chains, whereas cold dilute alkali extracted pectins with more numerous but shorter side-chains. No difference was pointed out neither in the quantity of polysaccharides extracted from the two genotypes studied nor in the composition of these constitutive polysaccharides.
    Carbohydrate Polymers 01/2002; DOI:10.1016/S0144-8617(01)00375-7 · 3.92 Impact Factor
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    Plant Biopolymer Science - Food and non-food applications, Edited by D. Renard, G. Della Valle, Y. Popineau, 01/2002: pages 55-62; Royal Society of Chemistry, Cambridge., ISBN: 0-85404-856-1
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    ABSTRACT: Water-soluble arabinoxylans have been fractionated from barley and barley malt by size exclusion chromatography to obtain high molar mass arabinoxylans involved in the viscosity of wort and beer. In both cases, five fractions were obtained: AXb1, AXb2, AXb3, AXb4 and AXb5 for barley and AXm1, AXm2, AXm3, AXm4 and AXm5 for barley malt. For barley and malt fractions, Ara/Xyl ratio, molar mass and intrinsic viscosity decreased as their elution volume increased. of barley fractions were higher than that of malt fractions, attesting arabinoxylans degradation during malting. NMR and methylation studies revealed that whatever the fractions, approximately 50% of the xylose residues were un-substituted. 2,3-Xyl level decreased from AXb1 to AXb5 and from AXm1 to AXm5, whereas 3-Xyl level increased at the same time. A non negligible amount of 2-Xyl was found, this level being almost the same (6–8%) for all the fractions. AXm1, which exhibited the highest intrinsic viscosity, (240 ml/g) was considered as an interesting fraction with regard to brewing problems. In spite of its highly branched structure, AXm1 was easily degraded by xylanases. Evidence for the presence of ferulic acid dimers in the water-soluble arabinoxylans from barley and barley malt is provided.
    Carbohydrate Polymers 01/2002; DOI:10.1016/S0144-8617(01)00172-2 · 3.92 Impact Factor
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    ABSTRACT: The covalent binding of laurylamine chains to maize bran heteroxylan (HX) was studied in order to produce hydrophobic plastic films. The process was carried out using periodic oxidation followed by reductive amination, both steps conducted in water. A kinetic study of the first step was performed, measuring periodate consumption, formic acid release and aldehyde formation. The over-oxidation effect was evaluated. The degree of substitution (DS) of dodecylamino-grafted-heteroxylan films ranged between 0.5 and 1.1 and varied as a function of experimental conditions. The maximal DS was reached under the following experimental conditions: NaIO4 2 eq per sugar unit, laurylamine 1.7 eq, NaBH3CN 5.8 eq per aldehyde. The plastic behaviour at room temperature was correlated to the glass transition temperature. Mechanical properties in function of the DS and the mode of obtention (casting, tape casting) were evaluated by tensile tests.
    Carbohydrate Polymers 01/2002; 49(1):1-12. DOI:10.1016/S0144-8617(01)00312-5 · 3.92 Impact Factor

Publication Stats

4k Citations
310.37 Total Impact Points

Institutions

  • 1986–2008
    • French National Institute for Agricultural Research
      • Biopolymères, Interactions, Assemblages (BIA)
      Lutetia Parisorum, Île-de-France, France
    • Wageningen University
      • Laboratory of Food Chemistry
      Wageningen, Gelderland, Netherlands
  • 1995–1998
    • New York State
      New York City, New York, United States
  • 1997
    • James Madison University
      Harrisonburg, Virginia, United States