References of "Razafindralambo, Hary"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailCharacterization of two Acacia gums and their fractions using a Langmuir film balance
Fauconnier, Marie-Laure ULiege; Blecker, Christophe ULiege; Groyne, J. et al

in Journal of Agricultural and Food Chemistry (2000), 48(7), 2709-2712

The mechanical properties of monolayers from two Acacia gums [Acacia senegal (L.) Willd. and Acacia seyal Del.] and their three fractions isolated by hydrophobic interaction chromatography were studied ... [more ▼]

The mechanical properties of monolayers from two Acacia gums [Acacia senegal (L.) Willd. and Acacia seyal Del.] and their three fractions isolated by hydrophobic interaction chromatography were studied with a Langmuir film balance to obtain a more complete understanding of their action mode. The analysis of compression isotherms revealed that A. senegal gums globally exhibit better interfacial properties than A. seyal ones. The behavior of the whole gums appeared to be strongly influenced by their arabinogalactan-protein complex. [less ▲]

Detailed reference viewed: 39 (8 ULiège)
Full Text
Peer Reviewed
See detailInteractions between gellan gum and other polysaccharides.
Blecker, Christophe ULiege; Razafindralambo, Hary ULiege; Paquot, Michel ULiege

in Czech Journal of Food Sciences (2000), 18

Detailed reference viewed: 38 (29 ULiège)
See detailRelationships between structure, interfacial properties, and functional qualities in foams and emulsions of surfactin, a lipopeptide from Bacillus subtilis.
Deleu, Magali ULiege; Paquot, Michel ULiege; Razafindralambo, Hary ULiege et al

Book published by Ed :E.Dickinson and J.M.R. Patino, Royal Society of Chemistry (1999)

Detailed reference viewed: 16 (6 ULiège)
Peer Reviewed
See detailStructure, interfacial properties, and functional qualities in foams and emulsions of surfactin, a lipopeptidefrom Bacillus subtilis
Deleu, Magali ULiege; Paquot, Michel ULiege; Razafindralambo, Hary ULiege et al

in Structure, Interfacial properties and functional qualities in foams (1999)

Detailed reference viewed: 18 (6 ULiège)
Full Text
Peer Reviewed
See detailComputer Simulation Of Surfactin Conformation At A Hydrophobic/Hydrophilic Interface
Gallet, X.; Deleu, Magali ULiege; Razafindralambo, Hary ULiege et al

in Langmuir (1999), 15(7), 2409-13

Using a molecular modeling method, different conformations of surfactin at a hydrophobic/hydrophilic interface are established. Two conformations of the peptide ring (S1 and S2) provided by NMR ... [more ▼]

Using a molecular modeling method, different conformations of surfactin at a hydrophobic/hydrophilic interface are established. Two conformations of the peptide ring (S1 and S2) provided by NMR experiments built with three different aliphatic chains in folded or extended configurations were studied. For the structures including the S2 peptide ring conformation, the theoretical interfacial molecular area corresponds to the experimental limiting area A0 value obtained with a Langmuir film balance. The peptide ring is positioned in the plane of the interface with the two acidic chains close to each other and protruding in the aqueous phase, and the β-hydroxy fatty acid chain, folded to interact mainly with the Leu2 side chain and also with the Val4 side chain. This design has the largest calculated molecular area and would correspond to the most stable amphipathic structure representing the surfactin experimental behavior in weak compression. [less ▲]

Detailed reference viewed: 22 (0 ULiège)
Full Text
Peer Reviewed
See detailInterfacial and emulsifying properties of lipopeptides from Bacillus subtilis
Deleu, Magali ULiege; Razafindralambo, Hary ULiege; Popineau, Y. et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (1999), 152(1-2), 3-10

The fundamental surface-active properties at the oil/water interface and emulsifying properties of surfactin, iturin A and fengycin, lipopeptides from Bacillus subtilis, were investigated. All ... [more ▼]

The fundamental surface-active properties at the oil/water interface and emulsifying properties of surfactin, iturin A and fengycin, lipopeptides from Bacillus subtilis, were investigated. All lipopeptides reduce rapidly the dynamic interfacial tension. Among lipopeptide families, surfactin is the most effective in terms of fundamental dynamic and equilibrium interfacial properties. Lipopeptides present intermediate properties in comparison with sodium dodecyl sulfate and beta-lactoglobulin concerning the stabilizing effect towards creaming-flocculation and the resistance to coalescence. Among lipopeptides, iturin A seems to show the best resistance to creaming-flocculation whereas fengycin exhibits the highest resistance to coalescence properties. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

Detailed reference viewed: 101 (6 ULiège)
Peer Reviewed
See detailOptimization of biosurfactant lipopeptide production from Bacillus subtilis S499 by Plackett-Burman design
Jacques, Philippe ULiege; Hbid, C.; Destain, Jacqueline ULiege et al

in Applied Biochemistry and Biotechnology (1999), 77-9

Bacillus subtilis S499 is well-known for its ability to produce two families of surfactant lipopeptides: Iturin A and Surfactin S1. Fermentation optimization for this strain was performed to amplify the ... [more ▼]

Bacillus subtilis S499 is well-known for its ability to produce two families of surfactant lipopeptides: Iturin A and Surfactin S1. Fermentation optimization for this strain was performed to amplify the surfactant production. Ten active variables were analyzed by two successive Plackett-Burman designs, consisting respectively of 12 and 16 experiments to give an optimized medium. The amount of biosurfactant lipopeptides in the supernatant of a culture carried out in this optimized medium was about five times higher than that obtained in nonoptimized rich medium. The analysis of the surfactant molecules produced in such optimized conditions has revealed the presence of a third family of lipopeptides: the fengycins. The time-dependent production of these three families of molecules in bioreactors showed that surfactin S1 is produced during the exponential phase and iturin A and fengycins during the stationary phase. [less ▲]

Detailed reference viewed: 238 (16 ULiège)
Peer Reviewed
See detailMixed monolayers of gluten-emulsifiers at the air-water interface
Balla, A.; Blecker, Christophe ULiege; Razafindralambo, Hary ULiege et al

in Biopolymer Science: Food And Non Food Applications (1999), (91), 213-216

The interactions and miscibility analysis of gluten-emulsifiers mixed film show that those films are not completely miscible as demonstrated by the presence of both two transition zones and also by the ... [more ▼]

The interactions and miscibility analysis of gluten-emulsifiers mixed film show that those films are not completely miscible as demonstrated by the presence of both two transition zones and also by the deviation of the mean molecular areas of mixed films from the values calculated according to the rule of additivity (GAINES, 1966). Furthermore, the free energy excess of mixing is positive in presence of emulsifiers, confirming the partial miscibility of gluten emulsifier monolayers. [less ▲]

Detailed reference viewed: 28 (4 ULiège)
See detailMixed monolayers of gluten-emulsifiers at the air-water interface.
Balla, A.; Blecker, Christophe ULiege; Razafindralambo, Hary ULiege et al

Poster (1998, September)

Detailed reference viewed: 11 (3 ULiège)
Full Text
Peer Reviewed
See detailFoaming properties of lipopeptides produced by Bacillus subtilis: effect of lipid and peptide structural attributes
Razafindralambo, Hary ULiege; Popineau, Yves; Deleu, Magali ULiege et al

in Journal of Agricultural and Food Chemistry (1998), 46(3), 911-916

To study the effect of lipid and peptide structural attributes of Bacillus subtilis lipopeptides on their foaming properties, the formation, stability, and appearance of foams prepared with surfactins ... [more ▼]

To study the effect of lipid and peptide structural attributes of Bacillus subtilis lipopeptides on their foaming properties, the formation, stability, and appearance of foams prepared with surfactins (C13 C15) and iturins A (C14 C17) were characterized. The density and stability of lipopeptide foams depend on both the alkyl chain hydrophobic character and peptide molecular intrinsic properties. A lipidic chain length of 14 carbon atoms provides lipopeptides with the best foaming properties in terms of foam density and liquid stability in foams. Increases in alkyl chain length above 15 carbon atoms result in a drastic decrease of iturin A foam density. With the same alkyl chain, surfactin produces denser foam whereas iturin A exhibits better foaming stability. These results demonstrate the importance of the peptide structural attributes of B. subtilis on their foaming properties. [less ▲]

Detailed reference viewed: 72 (35 ULiège)
Full Text
Peer Reviewed
See detailInterfacial Properties Of Gluten Monolayers Spread On Various Chloride Salt Solutions. Effects Of Electrolytes, Salt Concentrations, And Temperature
Balla, A.; Razafindralambo, Hary ULiege; Blecker, Christophe ULiege et al

in Journal of Agricultural and Food Chemistry (1998), 46(9), 3535-3539

The interfacial behavior of gluten powder spread as a monolayer on aqueous phases containing various chloride salts was studied. The presence of electrolytes at low concentrations reduced the expansion ... [more ▼]

The interfacial behavior of gluten powder spread as a monolayer on aqueous phases containing various chloride salts was studied. The presence of electrolytes at low concentrations reduced the expansion and stability of the gluten monolayers compared to the results obtained with pure water. At low salt concentrations, no effect of the electrolyte nature was detectable (compression curves were superimposed for Na+, K+, and Ca2+). However, when salt concentrations increased from 0.05 to 0.5 M, the influence of the electrolyte nature on gluten film expansion appeared clearly. Divalent cations (Ca2+) gave films with greater expansion than monovalent cations (K+, Na+). Between the monovalent cations, Na+ had a greater effect on gluten film expansion than did K+. Gluten monolayer expansion evaluated by limiting the area (A0) passed through a minimum when the salt concentrations increased from 0 to 0.5 M. The temperature also influenced the behavior of gluten monolayers as attested by A0 and film elasticity values which decreased with temperature. The energy of compression (ΔGc) that measures the intermolecular forces between film-forming molecules was generally higher on Ca2+ than on K+ and Na+, showing that Ca2+ induced stronger interactions than K+ or Na+. The ΔGc − T plots showed that the compression of gluten films on various electrolytes led to ordered structures. [less ▲]

Detailed reference viewed: 35 (22 ULiège)
See detailLipopeptides alter Bacillus subtilis hydrophobicity by adsorbing onto cell surfaces
Ahimou, François; Razafindralambo, Hary ULiege; Paquot, Michel ULiege

Poster (1997, October 29)

Detailed reference viewed: 13 (2 ULiège)
See detailSurface-active properties of surfactin-iturinA mixtures produced by Bacillus subtilis
Razafindralambo, Hary ULiege

Scientific conference (1997, March 16)

Detailed reference viewed: 13 (1 ULiège)
Full Text
Peer Reviewed
See detailSurface-active properties of surfactin iturin A mixtures produced by Bacillus subtilis
Razafindralambo, Hary ULiege; Popineau, Yves; Deleu, Magali ULiege et al

in Langmuir (1997), 13(23), 6026-6031

Surface-active properties including dynamic adsorption, monolayer stability, micelle forming capacity, and foaming aptitudes of surfactin-C-15/iturin A-C-15 mixtures were studied. Surfactin-C-15 and ... [more ▼]

Surface-active properties including dynamic adsorption, monolayer stability, micelle forming capacity, and foaming aptitudes of surfactin-C-15/iturin A-C-15 mixtures were studied. Surfactin-C-15 and iturin A-C-15 molecules interact in synergism on the most surface-active properties evaluated at 20 degrees C at the air-water interface and in aqueous solution (pH 8.0). The synergism is positive on the adsorption effect, monolayer stability, foam density, and liquid stability in foam, whereas it is negative on the adsorption rate. No synergism occurs an micelle forming capacity, but surfactin-C-15 and iturin A-C-15 form mixed micelles when the solution contains a low proportion of surfactin-C-15.ses the synergistic effect is maximum when surfactin-C-15 and iturin A-C-15 molecules are mixed in a 2:3 ratio. This is attributed to the surfactin/iturin A complex formation resulting from specific interactions among two surfactin-C-15 molecules and three iturin A-C-15 molecules. A model of such a complex formation is proposed. [less ▲]

Detailed reference viewed: 103 (45 ULiège)