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Papers by Francois Lamarche
Applied and Environmental Microbiology, 1998
Four inoculation techniques were compared for initiation of growth on cake surfaces: spot, air ca... more Four inoculation techniques were compared for initiation of growth on cake surfaces: spot, air cabinet, spray (atomizer), and talc addition methods. Molds were isolated from commercial cakes and were identified as Aspergillus sydowii , Aspergillus ochraceus , Penicillium funiculosum , and Eurotium herbariorum . Cake surfaces were inoculated with mold spores and incubated under three equilibrium relative humidity (ERH) levels: 97, 85, and 75%. Random contamination by spores in a ventilated air cabinet was the simplest method of inoculation, but standard deviations in the inoculation rates (20% on a relative scale) were almost twice those observed with the other methods. The spot method was the most reproducible. Cake samples inoculated in the air cabinet had colony counts 10 times lower than those obtained for potato dextrose agar plates at 97% ERH, which was not the case with the spray and talc methods. Growth of molds was much slower in the samples incubated in 75% relative humidit...
Biotechnology Progress, 2000
Desalination, May 1, 2006
Production of soy protein concentrates (SPC)/isolates (SPI) by traditional acidic precipitation, ... more Production of soy protein concentrates (SPC)/isolates (SPI) by traditional acidic precipitation, ultrafiltration, electro-acidification and a novel approach combining electro-acidification and ultrafiltration is reviewed. In the context of the development of a combined electro-acidification ultrafiltration process, the impact of electro-acidification on the filtration performance of soy protein extracts is investigated. The filtration performance is assessed for a two step process, diafiltration
Journal of Agricultural and Food Chemistry
Journal of Agricultural and Food Chemistry
Food technology
Colloids and Surfaces, 1987
ABSTRACT The binding of soluble cytochrome c to an insoluble monolayer of dioleoylphosphatidylcho... more ABSTRACT The binding of soluble cytochrome c to an insoluble monolayer of dioleoylphosphatidylcholine was studied. Surface pressure, surface potential and ellipsometric isotherms show that (i) cytochrome c is not adsorbed on a phosphatidylcholine monolayer compressed at 20 mN m−1, (ii) gradual incorporation of cytochrome c takes place as surface pressure decreases, and (iii) on recompression, the adsorbed protein is desorbed from the monolayer at 14 <Π (mN m−1) < 22. In order to determine if the results can be explained by intrinsic interfacial properties of phosphatidylcholine and cytochrome c taken separately, we measured surface pressure, surface potential and ellipsometric-area isotherms of pure cytochrome c which had been (i) deposited from crystals, (ii) deposited from ethanol:H2O Solution (2:1, v/v), and (iii) adsorbed at the air-water interface after injection into the subphase. Cytochrome c behaves like an insoluble monolayer at surface pressures lower than 8–10 mN m−1 and is gradually solubilized at higher surface pressures. Then, surface pressure regulates the organization of the protein at the air-water interface and the spreading solvent does not affect its conformation. Surface potential isotherms of mixed phosphatidylcholine (18:1) -cytochrome c films compressed at different surface pressures can be explained by the simple additivity rule. We show that continuous adsorption of cytochrome c occurs when the PC (18:1) film is compressed at surface pressures lower than 8–10 mN m−1. Beyond 14 mN m−1, both surface pressure-area and ellipsometric-area isotherms demonstrate complete desorption of soluble cytochrome c from the phosphatidylcholine monolayer. The applicability of such a model system to biomembranes is discussed.
Thin Solid Films, 1994
ABSTRACT The surface pressure Π-residual area A and the surface potential ΔV-residual area A isot... more ABSTRACT The surface pressure Π-residual area A and the surface potential ΔV-residual area A isotherms of poly-γ-benzyl-L-glutamate (PBLG) in the α-helical conformation have been studied at the air-water interface. We observe in the Π-A isotherm the monolayer-to-bilayer transition already reported in the literature. At large residual areas, ΔV is found to fluctuate, indicating that the PBLG molecules form aggregates. Indeed, these aggregates have been evidenced by epifluorescence microscopy. To gain further insights, we calculated the corresponding perpendicular dipolar moment μ⊥.μ⊥ decreases linearly with the decreasing apparent residual area from the onset of the transition. This is inconsistent with the fact that, during the transition, the surface area of the residues in contact with water should stay constant and accordingly the real μ⊥ should stay constant. In addition, immediately before the onset of the transition, the calculated μ⊥ values are found to be overestimated. We show that this fact results from an overestimation of the real surface area of the PBLG residues as a consequence of the existence of aggregates in this region. Finally, we propose that in such aggregates the surface area of PLBG residues must be similar to that found at the onset of the transition.
Trends in Food Science & Technology, 1998
Food Engineering Series, 2011
ABSTRACT Electrodialysis is a membrane technology that is used increasingly in the food sector to... more ABSTRACT Electrodialysis is a membrane technology that is used increasingly in the food sector to concentrate, purify, or modify the properties of foods. Electrodialysis can be performed in a dilution-concentration mode (conventional electrodialysis) when anion exchange and cation exchange membranes are used, or for pH modification when bipolar membranes are used (electrodialysis with bipolar membranes). Advantages of the technology include a modular design, product purification with no dilution, efficiency, pH variation and adjustment with no addition of external solutions, and the lack of requirements for additional thermal treatment. Today, the most important use of conventional electrodialysis is the desalination of brackish water for the production of potable water. However, other applications are gaining increasing importance including large-scale industrial installations in the food industry, whey and molasses demineralization, tartaric stabilization of wine, and deacidification of fruit juices). Electrodialysis using bipolar membranes is also used at the industrial scale to produce organic acid. Other applications currently under development that have potential for future industrial applications include the production of plant protein isolates, production of acid caseinates, fractionation of whey proteins, regeneration of wastewater resulting from food processing, and separation of peptides using an ultrafiltration–electrodialysis integrated process. The chapter summarizes some of the key industrial scale applications of both electrotechnologies in the food sector. Furthermore a few selected applications under development are briefly presented, with emphasis on the applications having the most potential to help in environmental protection.
Journal of Food Research, 2012
European Journal of Biochemistry, 1991
Langmuir, 1992
In order to mimic the packing of a-helices in a-helical proteins, two hydrophobic homopolypeptide... more In order to mimic the packing of a-helices in a-helical proteins, two hydrophobic homopolypeptides, poly-L-alanine (PLA) and poly-L-leucine (PLL), in their a-helical conformation were spread at the air/water interface and studied by the monolayer ...
Journal of the Science of Food and Agriculture, 2002
The aim of this study was to compare the electrochemical and chemical acidification of reconstitu... more The aim of this study was to compare the electrochemical and chemical acidification of reconstituted and fresh skim milk in terms of electrodialytic parameters, precipitation kinetics, chemical composition and physicochemical and functional properties of isolates produced ...
Journal of Membrane Science, 2005
The purpose of this work was to assess ionic transport, during electro-acidification of apple jui... more The purpose of this work was to assess ionic transport, during electro-acidification of apple juice, and its influence on the acidification rate and energy usage. In order to fulfill this objective, advanced current–voltage characterization of monopolar (cationic and anionic) and bipolar membranes was carried out. Experiments were conducted using two electrodialysis configurations (bipolar-cationic membranes and bipolar-anionic membranes) with two different
Journal of Membrane Science, 2000
Journal of Membrane Science, 2000
Applied and Environmental Microbiology, 1998
Four inoculation techniques were compared for initiation of growth on cake surfaces: spot, air ca... more Four inoculation techniques were compared for initiation of growth on cake surfaces: spot, air cabinet, spray (atomizer), and talc addition methods. Molds were isolated from commercial cakes and were identified as Aspergillus sydowii , Aspergillus ochraceus , Penicillium funiculosum , and Eurotium herbariorum . Cake surfaces were inoculated with mold spores and incubated under three equilibrium relative humidity (ERH) levels: 97, 85, and 75%. Random contamination by spores in a ventilated air cabinet was the simplest method of inoculation, but standard deviations in the inoculation rates (20% on a relative scale) were almost twice those observed with the other methods. The spot method was the most reproducible. Cake samples inoculated in the air cabinet had colony counts 10 times lower than those obtained for potato dextrose agar plates at 97% ERH, which was not the case with the spray and talc methods. Growth of molds was much slower in the samples incubated in 75% relative humidit...
Biotechnology Progress, 2000
Desalination, May 1, 2006
Production of soy protein concentrates (SPC)/isolates (SPI) by traditional acidic precipitation, ... more Production of soy protein concentrates (SPC)/isolates (SPI) by traditional acidic precipitation, ultrafiltration, electro-acidification and a novel approach combining electro-acidification and ultrafiltration is reviewed. In the context of the development of a combined electro-acidification ultrafiltration process, the impact of electro-acidification on the filtration performance of soy protein extracts is investigated. The filtration performance is assessed for a two step process, diafiltration
Journal of Agricultural and Food Chemistry
Journal of Agricultural and Food Chemistry
Food technology
Colloids and Surfaces, 1987
ABSTRACT The binding of soluble cytochrome c to an insoluble monolayer of dioleoylphosphatidylcho... more ABSTRACT The binding of soluble cytochrome c to an insoluble monolayer of dioleoylphosphatidylcholine was studied. Surface pressure, surface potential and ellipsometric isotherms show that (i) cytochrome c is not adsorbed on a phosphatidylcholine monolayer compressed at 20 mN m−1, (ii) gradual incorporation of cytochrome c takes place as surface pressure decreases, and (iii) on recompression, the adsorbed protein is desorbed from the monolayer at 14 <Π (mN m−1) < 22. In order to determine if the results can be explained by intrinsic interfacial properties of phosphatidylcholine and cytochrome c taken separately, we measured surface pressure, surface potential and ellipsometric-area isotherms of pure cytochrome c which had been (i) deposited from crystals, (ii) deposited from ethanol:H2O Solution (2:1, v/v), and (iii) adsorbed at the air-water interface after injection into the subphase. Cytochrome c behaves like an insoluble monolayer at surface pressures lower than 8–10 mN m−1 and is gradually solubilized at higher surface pressures. Then, surface pressure regulates the organization of the protein at the air-water interface and the spreading solvent does not affect its conformation. Surface potential isotherms of mixed phosphatidylcholine (18:1) -cytochrome c films compressed at different surface pressures can be explained by the simple additivity rule. We show that continuous adsorption of cytochrome c occurs when the PC (18:1) film is compressed at surface pressures lower than 8–10 mN m−1. Beyond 14 mN m−1, both surface pressure-area and ellipsometric-area isotherms demonstrate complete desorption of soluble cytochrome c from the phosphatidylcholine monolayer. The applicability of such a model system to biomembranes is discussed.
Thin Solid Films, 1994
ABSTRACT The surface pressure Π-residual area A and the surface potential ΔV-residual area A isot... more ABSTRACT The surface pressure Π-residual area A and the surface potential ΔV-residual area A isotherms of poly-γ-benzyl-L-glutamate (PBLG) in the α-helical conformation have been studied at the air-water interface. We observe in the Π-A isotherm the monolayer-to-bilayer transition already reported in the literature. At large residual areas, ΔV is found to fluctuate, indicating that the PBLG molecules form aggregates. Indeed, these aggregates have been evidenced by epifluorescence microscopy. To gain further insights, we calculated the corresponding perpendicular dipolar moment μ⊥.μ⊥ decreases linearly with the decreasing apparent residual area from the onset of the transition. This is inconsistent with the fact that, during the transition, the surface area of the residues in contact with water should stay constant and accordingly the real μ⊥ should stay constant. In addition, immediately before the onset of the transition, the calculated μ⊥ values are found to be overestimated. We show that this fact results from an overestimation of the real surface area of the PBLG residues as a consequence of the existence of aggregates in this region. Finally, we propose that in such aggregates the surface area of PLBG residues must be similar to that found at the onset of the transition.
Trends in Food Science & Technology, 1998
Food Engineering Series, 2011
ABSTRACT Electrodialysis is a membrane technology that is used increasingly in the food sector to... more ABSTRACT Electrodialysis is a membrane technology that is used increasingly in the food sector to concentrate, purify, or modify the properties of foods. Electrodialysis can be performed in a dilution-concentration mode (conventional electrodialysis) when anion exchange and cation exchange membranes are used, or for pH modification when bipolar membranes are used (electrodialysis with bipolar membranes). Advantages of the technology include a modular design, product purification with no dilution, efficiency, pH variation and adjustment with no addition of external solutions, and the lack of requirements for additional thermal treatment. Today, the most important use of conventional electrodialysis is the desalination of brackish water for the production of potable water. However, other applications are gaining increasing importance including large-scale industrial installations in the food industry, whey and molasses demineralization, tartaric stabilization of wine, and deacidification of fruit juices). Electrodialysis using bipolar membranes is also used at the industrial scale to produce organic acid. Other applications currently under development that have potential for future industrial applications include the production of plant protein isolates, production of acid caseinates, fractionation of whey proteins, regeneration of wastewater resulting from food processing, and separation of peptides using an ultrafiltration–electrodialysis integrated process. The chapter summarizes some of the key industrial scale applications of both electrotechnologies in the food sector. Furthermore a few selected applications under development are briefly presented, with emphasis on the applications having the most potential to help in environmental protection.
Journal of Food Research, 2012
European Journal of Biochemistry, 1991
Langmuir, 1992
In order to mimic the packing of a-helices in a-helical proteins, two hydrophobic homopolypeptide... more In order to mimic the packing of a-helices in a-helical proteins, two hydrophobic homopolypeptides, poly-L-alanine (PLA) and poly-L-leucine (PLL), in their a-helical conformation were spread at the air/water interface and studied by the monolayer ...
Journal of the Science of Food and Agriculture, 2002
The aim of this study was to compare the electrochemical and chemical acidification of reconstitu... more The aim of this study was to compare the electrochemical and chemical acidification of reconstituted and fresh skim milk in terms of electrodialytic parameters, precipitation kinetics, chemical composition and physicochemical and functional properties of isolates produced ...
Journal of Membrane Science, 2005
The purpose of this work was to assess ionic transport, during electro-acidification of apple jui... more The purpose of this work was to assess ionic transport, during electro-acidification of apple juice, and its influence on the acidification rate and energy usage. In order to fulfill this objective, advanced current–voltage characterization of monopolar (cationic and anionic) and bipolar membranes was carried out. Experiments were conducted using two electrodialysis configurations (bipolar-cationic membranes and bipolar-anionic membranes) with two different
Journal of Membrane Science, 2000
Journal of Membrane Science, 2000