La presente invention concerne des compositions solides comprenant des agents bioactifs, en parti... more La presente invention concerne des compositions solides comprenant des agents bioactifs, en particulier des microorganismes probiotiques. De plus, la presente invention concerne des procedes pour preparer des compositions de l'invention, comprenant l'etape de microencapsulation de microorganismes vivants pour produire une formulation seche et, facultativement, enrober les microcapsules, tout en conservant dans une mesure significative la viabilite des microorganismes.
The association behavior, critical micellization concentration (CMC), and enthalpy of demicelliza... more The association behavior, critical micellization concentration (CMC), and enthalpy of demicellization (DeltaHdemic) of bovine beta-casein were studied, for the first time by isothermal titration calorimetry, in a pH 7.0 phosphate buffer with 0.1 ionic strength and in pure water. In the buffer solutions, the CMC decreased asymptotically from 0.15 to 0.006 mM as the temperature was raised from 16 to 45 degrees C. DeltaHdemic decreased with increasing temperature between 16 and 28 degrees C but increased from 28 to 45 degrees C. Thermodynamic analysis below 30 degrees C is consistent with the Kegeles shell model, which suggests a stepwise association process. At higher temperatures, this model exhibits limitations, and the micellization becomes much more cooperative. The CMC values in water, measured between 17 and 28 degrees C, decreased with increasing temperature and, expectedly, were higher than those found in the buffer solutions. beta-Casein micelles were visualized and character...
In the present research, an air-suspension fluidized-bed technique for generation of core and she... more In the present research, an air-suspension fluidized-bed technique for generation of core and shell microcapsules containing probiotic Lactobacillusparacasei cells was evaluated. The air-suspension process was performed in a Wu¨rster coater system with a bottomspraying atomizer. In the first stage, a solution containing trehalose, maltodextrin, and probiotic cells was spray-coated onto and absorbed by the inert carrier microcrystalline cellulose to produce nonagglomerating dry coated particles with high probiotic cell viability (109 colony-forming units [cfu]/g particles). The effect of inlet air temperature, spray flow rate, solids concentration, cell concentration, and encapsulation formulation on survival was investigated. The inlet air temperature had the most pronounced effect; a 15�C increase in inlet air temperature led to a 250-fold decrease in survival percentage. There was no agglomeration of the coated adsorbed particles at spray flow rates of 1 to 3.5 mL/min. Spraycoatin...
Abstract Ultrasonic vacuum spray dryer was used to produce a dry powder of highly viable probioti... more Abstract Ultrasonic vacuum spray dryer was used to produce a dry powder of highly viable probiotic cells. The drying was performed through two stages: Vacuum spray drying of the solution followed by fluidized-bed drying of the powder. The embedding matrix was a ...
This study evaluated the use of enzymatically synthesized dextran nanoparticles to entrap a hydro... more This study evaluated the use of enzymatically synthesized dextran nanoparticles to entrap a hydrophobic nutraceutical, the isoflavone genistein. The focus was on the synthesis of pure dextran as the material for the entire nanoparticle, and their inclusion-complexation of genistein. Under optimal conditions (pH 5.2-6 and sucrose concentration >0.5 M), dextransucrase generated spherical dextran nanoparticles (100-450 nm). The two nutraceutical inclusion methods were DMSO dilution in water and acidification. Optimization of the inclusion processes produced nanosized dextran particles containing genistein. The DMSO method was found to be more suitable for inclusion of genistein in dextran, resulting in a higher genistein load (5.6 ± 0.1 g genistein per 100 g particles), and a higher percentage of nanosized particles (85%, 105-400 nm). For both protocols, addition of a freeze-drying step exerted a positive effect presumably due to the formation of new hydrogen bonds and van der Waals...
ABSTRACT Cushioning curves for different plastic foams were determined using drop and shock tests... more ABSTRACT Cushioning curves for different plastic foams were determined using drop and shock tests. It was found that at intermediate static stresses the two methods give comparable results. At low and very high static stresses however, different results were obtained. An explanation was given why the shock test is more appropriate and reliable at low and the drop test at very high static stresses.
It is also possible that your web browser is not configured or not able to display style sheets. ... more It is also possible that your web browser is not configured or not able to display style sheets. In this case, although the visual presentation will be degraded, the site should continue to be functional. We recommend using the latest version of Microsoft or Mozilla web browser to ...
... Inna Shechter § , Ory ... Equally contributing authors. Abstract. Abstract Image. The LCST p... more ... Inna Shechter § , Ory ... Equally contributing authors. Abstract. Abstract Image. The LCST phase-transition of aqueous PNIPA solutions in rising concentrations of the strong chaotropic salt KSCN was studied microcalorimetrically by DSC and apparently for the first time by ITC. ...
beta-Casein is one of the main proteins in milk, recently classified as an intrinsically unstruct... more beta-Casein is one of the main proteins in milk, recently classified as an intrinsically unstructured protein. At neutral pH, it is composed of a highly polar N-terminus domain and a hydrophobic C-terminus tail. This amphiphilic block-copolymer-like structure leads to self-organization of the protein monomers into defined micelles. Recently, it has been shown that at room temperature, beta-casein also self-organizes into micelles in an acidic environment, but the effect of temperature on the micelles' formation and properties at the low pH regime were not explored. In the present study, we used two complementary techniques, cryogenic-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS), to characterize at high-resolution the micelles' shape, dimensions, and aggregation numbers and to determine how these properties are affected by temperature between 1 and 40 degrees C. Two different regimes were studied: highly acidic pH where the protein is cationic, and neutral pH, where it is anionic. We found that flat disk-like micelles with low aggregation numbers formed at low temperature in the two pH regimes. Close to neutral pH increase in temperature involves a transition in the micelles' shape and dimensions from flat disks to bulky, almost spheroidal micelles, coupled with a sharp increase in the micelles' aggregation number. In contrast, no effects on the micelles' morphology or aggregation number were detected in the acidic environment within the entire temperature range studied. The self-organization into disk micelles and the lack of effect of temperature in the acidic environment are linked to the unstructured character of the protein and to the charge distribution map. The latter indicates that below the isoelectric pH (pI), beta-casein loses the distinct separation of hydrophobic and hydrophilic domains, thereby suggesting that it may no longer be considered as a classical head-tail block-copolymer amphiphile as in neutral pH.
La presente invention concerne des compositions solides comprenant des agents bioactifs, en parti... more La presente invention concerne des compositions solides comprenant des agents bioactifs, en particulier des microorganismes probiotiques. De plus, la presente invention concerne des procedes pour preparer des compositions de l'invention, comprenant l'etape de microencapsulation de microorganismes vivants pour produire une formulation seche et, facultativement, enrober les microcapsules, tout en conservant dans une mesure significative la viabilite des microorganismes.
The association behavior, critical micellization concentration (CMC), and enthalpy of demicelliza... more The association behavior, critical micellization concentration (CMC), and enthalpy of demicellization (DeltaHdemic) of bovine beta-casein were studied, for the first time by isothermal titration calorimetry, in a pH 7.0 phosphate buffer with 0.1 ionic strength and in pure water. In the buffer solutions, the CMC decreased asymptotically from 0.15 to 0.006 mM as the temperature was raised from 16 to 45 degrees C. DeltaHdemic decreased with increasing temperature between 16 and 28 degrees C but increased from 28 to 45 degrees C. Thermodynamic analysis below 30 degrees C is consistent with the Kegeles shell model, which suggests a stepwise association process. At higher temperatures, this model exhibits limitations, and the micellization becomes much more cooperative. The CMC values in water, measured between 17 and 28 degrees C, decreased with increasing temperature and, expectedly, were higher than those found in the buffer solutions. beta-Casein micelles were visualized and character...
In the present research, an air-suspension fluidized-bed technique for generation of core and she... more In the present research, an air-suspension fluidized-bed technique for generation of core and shell microcapsules containing probiotic Lactobacillusparacasei cells was evaluated. The air-suspension process was performed in a Wu¨rster coater system with a bottomspraying atomizer. In the first stage, a solution containing trehalose, maltodextrin, and probiotic cells was spray-coated onto and absorbed by the inert carrier microcrystalline cellulose to produce nonagglomerating dry coated particles with high probiotic cell viability (109 colony-forming units [cfu]/g particles). The effect of inlet air temperature, spray flow rate, solids concentration, cell concentration, and encapsulation formulation on survival was investigated. The inlet air temperature had the most pronounced effect; a 15�C increase in inlet air temperature led to a 250-fold decrease in survival percentage. There was no agglomeration of the coated adsorbed particles at spray flow rates of 1 to 3.5 mL/min. Spraycoatin...
Abstract Ultrasonic vacuum spray dryer was used to produce a dry powder of highly viable probioti... more Abstract Ultrasonic vacuum spray dryer was used to produce a dry powder of highly viable probiotic cells. The drying was performed through two stages: Vacuum spray drying of the solution followed by fluidized-bed drying of the powder. The embedding matrix was a ...
This study evaluated the use of enzymatically synthesized dextran nanoparticles to entrap a hydro... more This study evaluated the use of enzymatically synthesized dextran nanoparticles to entrap a hydrophobic nutraceutical, the isoflavone genistein. The focus was on the synthesis of pure dextran as the material for the entire nanoparticle, and their inclusion-complexation of genistein. Under optimal conditions (pH 5.2-6 and sucrose concentration >0.5 M), dextransucrase generated spherical dextran nanoparticles (100-450 nm). The two nutraceutical inclusion methods were DMSO dilution in water and acidification. Optimization of the inclusion processes produced nanosized dextran particles containing genistein. The DMSO method was found to be more suitable for inclusion of genistein in dextran, resulting in a higher genistein load (5.6 ± 0.1 g genistein per 100 g particles), and a higher percentage of nanosized particles (85%, 105-400 nm). For both protocols, addition of a freeze-drying step exerted a positive effect presumably due to the formation of new hydrogen bonds and van der Waals...
ABSTRACT Cushioning curves for different plastic foams were determined using drop and shock tests... more ABSTRACT Cushioning curves for different plastic foams were determined using drop and shock tests. It was found that at intermediate static stresses the two methods give comparable results. At low and very high static stresses however, different results were obtained. An explanation was given why the shock test is more appropriate and reliable at low and the drop test at very high static stresses.
It is also possible that your web browser is not configured or not able to display style sheets. ... more It is also possible that your web browser is not configured or not able to display style sheets. In this case, although the visual presentation will be degraded, the site should continue to be functional. We recommend using the latest version of Microsoft or Mozilla web browser to ...
... Inna Shechter § , Ory ... Equally contributing authors. Abstract. Abstract Image. The LCST p... more ... Inna Shechter § , Ory ... Equally contributing authors. Abstract. Abstract Image. The LCST phase-transition of aqueous PNIPA solutions in rising concentrations of the strong chaotropic salt KSCN was studied microcalorimetrically by DSC and apparently for the first time by ITC. ...
beta-Casein is one of the main proteins in milk, recently classified as an intrinsically unstruct... more beta-Casein is one of the main proteins in milk, recently classified as an intrinsically unstructured protein. At neutral pH, it is composed of a highly polar N-terminus domain and a hydrophobic C-terminus tail. This amphiphilic block-copolymer-like structure leads to self-organization of the protein monomers into defined micelles. Recently, it has been shown that at room temperature, beta-casein also self-organizes into micelles in an acidic environment, but the effect of temperature on the micelles' formation and properties at the low pH regime were not explored. In the present study, we used two complementary techniques, cryogenic-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS), to characterize at high-resolution the micelles' shape, dimensions, and aggregation numbers and to determine how these properties are affected by temperature between 1 and 40 degrees C. Two different regimes were studied: highly acidic pH where the protein is cationic, and neutral pH, where it is anionic. We found that flat disk-like micelles with low aggregation numbers formed at low temperature in the two pH regimes. Close to neutral pH increase in temperature involves a transition in the micelles' shape and dimensions from flat disks to bulky, almost spheroidal micelles, coupled with a sharp increase in the micelles' aggregation number. In contrast, no effects on the micelles' morphology or aggregation number were detected in the acidic environment within the entire temperature range studied. The self-organization into disk micelles and the lack of effect of temperature in the acidic environment are linked to the unstructured character of the protein and to the charge distribution map. The latter indicates that below the isoelectric pH (pI), beta-casein loses the distinct separation of hydrophobic and hydrophilic domains, thereby suggesting that it may no longer be considered as a classical head-tail block-copolymer amphiphile as in neutral pH.
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