Isabel Coelhoso - Academia.edu (original) (raw)
Papers by Isabel Coelhoso
Polymers
Dicarboxymethyl cellulose (DCMC) was synthesized and tested for protein adsorption. The prepared ... more Dicarboxymethyl cellulose (DCMC) was synthesized and tested for protein adsorption. The prepared polymer was characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and solid state nuclear magnetic resonance (ssNMR) to confirm the functionalization of cellulose. This work shows that protein adsorption onto DCMC is charge dependent. The polymer adsorbs positively charged proteins, cytochrome C and lysozyme, with adsorption capacities of 851 and 571 mg g−1, respectively. In both experiments, the adsorption process follows the Langmuir adsorption isotherm. The adsorption kinetics by DCMC is well described by the pseudo second-order model, and adsorption equilibrium was reached within 90 min. Moreover, DCMC was successfully reused for five consecutive adsorption–desorption cycles, without compromising the removal efficiency (98–99%).
www.mdpi.com/journal/membranes
Carla Martins, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universi... more Carla Martins, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal cmm17205@campus.fct.unl.pt Luísa Neves, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal Carlos Afonso, Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal Isabel Coelhoso, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal João Crespo, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Food Packaging and Shelf Life, 2021
Abstract The purpose of this study was to investigate the potential of cranberry extract as a val... more Abstract The purpose of this study was to investigate the potential of cranberry extract as a valuable antibiofilm additive of chitosan-based films intended for food packaging applications. Two types of chitosan-based films differing in the plasticizers content (PEG alone or PEG and glycerol) were prepared by casting methodology. Cranberry-extracts were proven to be suitable for presenting antioxidant (i.e. DPPH scavenging ability) and antimicrobial activity (towards Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923). Additionally, among phenolic compounds present, responsible for those activities were isorhamnetin-3-glucoside, hydroxybenzoic acid, phloridzin, pelargonidin, chlorogenic acid, epicatechin and A-type procyanidin that were identified by HPLC-MS/MS. Films incorporating cranberry extracts showed adequate food preservation characteristics (light transmission, water and oxygen permeability). Produced films were also able to quench DPPH radical by 92.2 ± 3.9 (PEG added) and 89.7 ± 0.7 % (PEG and glycerol added) and inhibit E. coli and S. aureus biofilm formation. Concerning E. coli, a reduction of 5 and 4 log units was obtained with films added of PEG or PEG/glycerol, respectively. Remarkably, both chitosan-films completely prevented S. aureus biofilm. The obtained results place cranberry-chitosan films as a potential option for food packaging with antioxidant and antibiofilm properties as added value.
Chitin- and Chitosan-Based Biocomposites for Food Packaging Applications, 2020
Membranes, 2020
A novel cellulose-based cross-linked polymer, dicarboxymethyl cellulose (DCMC), has been synthesi... more A novel cellulose-based cross-linked polymer, dicarboxymethyl cellulose (DCMC), has been synthesized and used for methylene blue (MB) removal. Inductively coupled plasma atomic emission spectrometry (ICP-AES), Fourier-transform infrared spectroscopy (FTIR), nitrogen porosimetry, and optical microscopy were employed to characterize the structure of the cellulose-based adsorbent. The number of carboxylate groups per gram of polymer (CG) was calculated with sodium content determined by ICP-AES. Systematic equilibrium and kinetic adsorption studies were performed to assess the polymer suitability for dye removal. The effect of pH on its adsorption capacity was also studied and the equilibrium adsorption data was analyzed using Langmuir, Freundlich, and Sips isotherms. At pH = 3, the adsorption isotherms followed the Langmuir model with a maximum adsorption capacity of 887.6 mg/g. At pH = 6.4, the adsorption isotherms produced S-shape curves and were best fitted with the Sips model. The ...
Molecules, 2019
Membrane distillation (MD) has recently gained considerable attention as a valid process for the ... more Membrane distillation (MD) has recently gained considerable attention as a valid process for the production of fresh-water due to its ability to exploit low grade waste heat for operation and to ensure a nearly feed concentration-independent production of high-purity distillate. Limitations have been related to polarization phenomena negatively affecting the thermal efficiency of the process and, as a consequence, its productivity. Several theoretical models have been developed to predict the impact of the operating conditions of the process on the thermal polarization, but there is a lack of experimental validation. In this study, electrospun nanofiber membranes (ENMs) made of Poly(vinylidene fluoride) (PVDF) and doped with (1, 10-phenanthroline) ruthenium (II) Ru(phen)3 were tested at different operating conditions (i.e., temperature and velocity of the feed) in direct contact membrane distillation (DCMD). The temperature sensitive luminophore, Ru(phen)3, allowed the on-line and n...
Dissertação apresentada para obtenção do grau de Mestre, na Faculdade de Engenharia da Universida... more Dissertação apresentada para obtenção do grau de Mestre, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor Alírio Rodrigue
Coatings, 2022
Traditional food packaging systems help reduce food wastage, but they also produce environmental ... more Traditional food packaging systems help reduce food wastage, but they also produce environmental impacts when not properly disposed of. Bio-based polymers are a promising solution to overcome these impacts, but they have poor barrier and mechanical properties. This work evaluates two strategies to improve these properties in pectin films: the incorporation of cellulose nanocrystals (CNC) or sodium montmorillonite (MMT) nanoparticles, and an additional layer of chitosan (i.e., a bilayer film). The bionanocomposites and bilayer films were characterized in terms of optical, morphological, hygroscopic, mechanical and barrier properties. The inclusion of the nanofillers in the polymer reduced the water vapor permeability and the hydrophilicity of the films without compromising their visual properties (i.e., their transparency). However, the nanoparticles did not substantially improve the mechanical properties of the bionanocomposites. Regarding the bilayer films, FTIR and contact angle s...
Membranes, 2021
Protein crystallization still remains mostly an empirical science, as the production of crystals ... more Protein crystallization still remains mostly an empirical science, as the production of crystals with the required quality for X-ray analysis is dependent on the intensive screening of the best protein crystallization and crystal’s derivatization conditions. Herein, this demanding step was addressed by the development of a high-throughput and low-budget microfluidic platform consisting of an ion exchange membrane (117 Nafion® membrane) sandwiched between a channel layer (stripping phase compartment) and a wells layer (feed phase compartment) forming 75 independent micro-contactors. This microfluidic device allows for a simultaneous and independent screening of multiple protein crystallization and crystal derivatization conditions, using Hen Egg White Lysozyme (HEWL) as the model protein and Hg2+ as the derivatizing agent. This microdevice offers well-regulated crystallization and subsequent crystal derivatization processes based on the controlled transport of water and ions provided...
Membranes, Jan 28, 2016
In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, B... more In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, Black, and Forest Fruit teas) using the osmotic evaporation (OE) process, was studied. The effect of the OE process on the content of phenolic compounds and antioxidant activity was evaluated. The concentration process was carried out in a hollow-fibre membrane contactor with an effective surface area of 0.54 m². The tea extract was circulated through the shell side of the contactor, while a concentrated osmotic solution (CaCl₂ 5 M) was circulated inside the fibres. The flux, the driving force, and the mass transfer coefficient were evaluated. A decrease of the water flux over time was observed and was attributed only to the decrease of the driving force, caused by the dilution of the osmotic solution. Using a surface area/feed volume ratio of 774 m²·m(-3), it is possible to reach a tea concentration of 40% (w/w) in 5 h, with a constant water flux and without losing the phenolic content a...
Membranes, 2016
Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfi... more Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications.
Journal of Membrane Science, 2010
International Journal of Biological Macromolecules, 2015
In this work, the solution properties of the bacterial fucose-rich polysaccharide, FucoPol, were ... more In this work, the solution properties of the bacterial fucose-rich polysaccharide, FucoPol, were studied. The effect of pH (3.5-10.0) and ionic strength (0.02-1.0 M NaCl) on the intrinsic viscosity and steady shear flow were evaluated using a central composite rotatable design of experiments and surface response methodology. FucoPol's intrinsic and apparent viscosities presented a quite low variation under a wide range of pH (3.5-8.0) and ionic strength (0.05-0.50 M NaCl) values. FucoPol produced viscous solutions with shear-thinning behavior at different polymer concentrations (0.2-1.2 wt.%). Flow curves were successfully described by the Cross model. The viscosity of the first Newtonian plateau varied from 0.01 to 2.47 Pa s for polymer concentrations from 0.2 to 1.2 wt.%, and the dependence of the estimated relaxation time with polymer concentration suggests a large degree of interaction between FucoPol molecules. Given the results obtained, FucoPol is proposed as thickening agent for applications in which stability of the apparent viscosity under pH and ionic strength variations is required.
The objective of this work is to develop model composite films based on commercial pectin and k-c... more The objective of this work is to develop model composite films based on commercial pectin and k-carrageen, containing mica particles as impermeable barriers, and to characterize them in terms of their hygroscopic and permeability to water vapour and gases (oxygen and carbon dioxide). The water adsorption capacity of the polymer/mica films seemed to be independent of the amount of mica added, showing a rather constant sorption coefficient. Regarding the water vapour permeability, a decrease was observed with the inclusion of mica, until a minimum value of 5.8 x 10 -11 mol/ (m s Pa) with 10% (dry weight) of mica particles added. As expected, these films are more permeable to water vapour than to O 2 and CO 2 . The CO 2 and O 2 permeability of the films is four orders of magnitude lower than their water vapour permeability and decreases with the increase of mica content in the film. The films presented good barrier properties to gases, and their water vapour and gas permeability was re...
Procedia Food Science, 2011
In this work the barrier properties of biodegradable films for food packaging using commercial pe... more In this work the barrier properties of biodegradable films for food packaging using commercial pectin and kcarrageenan and nanoclays organically modified were studied. Films (67% k-carrageenan) and different amounts of nanoclays (1, 5 and 10%) were prepared by casting. A pronounced decrease in the water vapour permeability with the higher driving force used (RH 92%-65%) is observed. It reduces about 35% of its initial value at 10% nanoclay content. The films permeability to carbon dioxide also reduces 50% for 1% nanoclay content. Films barrier properties may be further improved by enhancing the particles dispersion and exfoliation degree.
Journal of Membrane Science, 2013
Journal of Food Engineering, 2006
In this work, the osmotic evaporation (OE) and membrane distillation (MD) processes were compared... more In this work, the osmotic evaporation (OE) and membrane distillation (MD) processes were compared in terms of water flux and aroma retention. The concentration of a sucrose solution, used as a model fruit juice, was carried out in a hollow fibre membrane contactor. ...
Journal of Applied Polymer Science, 2013
Microbial polysaccharides are characterized by high molecular structure variability which transla... more Microbial polysaccharides are characterized by high molecular structure variability which translates into a wide range of different properties offering interesting opportunities for application in many different areas, including membrane-based products and processes. Due to their new or improved properties, microbial polysaccharides can replace plant, algae, and animal products, either in their traditional or in new applications. The main constraint to their wider use is the production costs that are still higher than that of other natural and synthetic polymers. The current applications of microbial polysaccharide membranes in medical, food, and industrial processes are outlined. The limitations still faced by these membranes and the requirements for obtaining innovative products and processes are also addressed.
Polymers
Dicarboxymethyl cellulose (DCMC) was synthesized and tested for protein adsorption. The prepared ... more Dicarboxymethyl cellulose (DCMC) was synthesized and tested for protein adsorption. The prepared polymer was characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and solid state nuclear magnetic resonance (ssNMR) to confirm the functionalization of cellulose. This work shows that protein adsorption onto DCMC is charge dependent. The polymer adsorbs positively charged proteins, cytochrome C and lysozyme, with adsorption capacities of 851 and 571 mg g−1, respectively. In both experiments, the adsorption process follows the Langmuir adsorption isotherm. The adsorption kinetics by DCMC is well described by the pseudo second-order model, and adsorption equilibrium was reached within 90 min. Moreover, DCMC was successfully reused for five consecutive adsorption–desorption cycles, without compromising the removal efficiency (98–99%).
www.mdpi.com/journal/membranes
Carla Martins, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universi... more Carla Martins, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal cmm17205@campus.fct.unl.pt Luísa Neves, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal Carlos Afonso, Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal Isabel Coelhoso, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal João Crespo, LAQV, Requimte, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Food Packaging and Shelf Life, 2021
Abstract The purpose of this study was to investigate the potential of cranberry extract as a val... more Abstract The purpose of this study was to investigate the potential of cranberry extract as a valuable antibiofilm additive of chitosan-based films intended for food packaging applications. Two types of chitosan-based films differing in the plasticizers content (PEG alone or PEG and glycerol) were prepared by casting methodology. Cranberry-extracts were proven to be suitable for presenting antioxidant (i.e. DPPH scavenging ability) and antimicrobial activity (towards Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923). Additionally, among phenolic compounds present, responsible for those activities were isorhamnetin-3-glucoside, hydroxybenzoic acid, phloridzin, pelargonidin, chlorogenic acid, epicatechin and A-type procyanidin that were identified by HPLC-MS/MS. Films incorporating cranberry extracts showed adequate food preservation characteristics (light transmission, water and oxygen permeability). Produced films were also able to quench DPPH radical by 92.2 ± 3.9 (PEG added) and 89.7 ± 0.7 % (PEG and glycerol added) and inhibit E. coli and S. aureus biofilm formation. Concerning E. coli, a reduction of 5 and 4 log units was obtained with films added of PEG or PEG/glycerol, respectively. Remarkably, both chitosan-films completely prevented S. aureus biofilm. The obtained results place cranberry-chitosan films as a potential option for food packaging with antioxidant and antibiofilm properties as added value.
Chitin- and Chitosan-Based Biocomposites for Food Packaging Applications, 2020
Membranes, 2020
A novel cellulose-based cross-linked polymer, dicarboxymethyl cellulose (DCMC), has been synthesi... more A novel cellulose-based cross-linked polymer, dicarboxymethyl cellulose (DCMC), has been synthesized and used for methylene blue (MB) removal. Inductively coupled plasma atomic emission spectrometry (ICP-AES), Fourier-transform infrared spectroscopy (FTIR), nitrogen porosimetry, and optical microscopy were employed to characterize the structure of the cellulose-based adsorbent. The number of carboxylate groups per gram of polymer (CG) was calculated with sodium content determined by ICP-AES. Systematic equilibrium and kinetic adsorption studies were performed to assess the polymer suitability for dye removal. The effect of pH on its adsorption capacity was also studied and the equilibrium adsorption data was analyzed using Langmuir, Freundlich, and Sips isotherms. At pH = 3, the adsorption isotherms followed the Langmuir model with a maximum adsorption capacity of 887.6 mg/g. At pH = 6.4, the adsorption isotherms produced S-shape curves and were best fitted with the Sips model. The ...
Molecules, 2019
Membrane distillation (MD) has recently gained considerable attention as a valid process for the ... more Membrane distillation (MD) has recently gained considerable attention as a valid process for the production of fresh-water due to its ability to exploit low grade waste heat for operation and to ensure a nearly feed concentration-independent production of high-purity distillate. Limitations have been related to polarization phenomena negatively affecting the thermal efficiency of the process and, as a consequence, its productivity. Several theoretical models have been developed to predict the impact of the operating conditions of the process on the thermal polarization, but there is a lack of experimental validation. In this study, electrospun nanofiber membranes (ENMs) made of Poly(vinylidene fluoride) (PVDF) and doped with (1, 10-phenanthroline) ruthenium (II) Ru(phen)3 were tested at different operating conditions (i.e., temperature and velocity of the feed) in direct contact membrane distillation (DCMD). The temperature sensitive luminophore, Ru(phen)3, allowed the on-line and n...
Dissertação apresentada para obtenção do grau de Mestre, na Faculdade de Engenharia da Universida... more Dissertação apresentada para obtenção do grau de Mestre, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor Alírio Rodrigue
Coatings, 2022
Traditional food packaging systems help reduce food wastage, but they also produce environmental ... more Traditional food packaging systems help reduce food wastage, but they also produce environmental impacts when not properly disposed of. Bio-based polymers are a promising solution to overcome these impacts, but they have poor barrier and mechanical properties. This work evaluates two strategies to improve these properties in pectin films: the incorporation of cellulose nanocrystals (CNC) or sodium montmorillonite (MMT) nanoparticles, and an additional layer of chitosan (i.e., a bilayer film). The bionanocomposites and bilayer films were characterized in terms of optical, morphological, hygroscopic, mechanical and barrier properties. The inclusion of the nanofillers in the polymer reduced the water vapor permeability and the hydrophilicity of the films without compromising their visual properties (i.e., their transparency). However, the nanoparticles did not substantially improve the mechanical properties of the bionanocomposites. Regarding the bilayer films, FTIR and contact angle s...
Membranes, 2021
Protein crystallization still remains mostly an empirical science, as the production of crystals ... more Protein crystallization still remains mostly an empirical science, as the production of crystals with the required quality for X-ray analysis is dependent on the intensive screening of the best protein crystallization and crystal’s derivatization conditions. Herein, this demanding step was addressed by the development of a high-throughput and low-budget microfluidic platform consisting of an ion exchange membrane (117 Nafion® membrane) sandwiched between a channel layer (stripping phase compartment) and a wells layer (feed phase compartment) forming 75 independent micro-contactors. This microfluidic device allows for a simultaneous and independent screening of multiple protein crystallization and crystal derivatization conditions, using Hen Egg White Lysozyme (HEWL) as the model protein and Hg2+ as the derivatizing agent. This microdevice offers well-regulated crystallization and subsequent crystal derivatization processes based on the controlled transport of water and ions provided...
Membranes, Jan 28, 2016
In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, B... more In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, Black, and Forest Fruit teas) using the osmotic evaporation (OE) process, was studied. The effect of the OE process on the content of phenolic compounds and antioxidant activity was evaluated. The concentration process was carried out in a hollow-fibre membrane contactor with an effective surface area of 0.54 m². The tea extract was circulated through the shell side of the contactor, while a concentrated osmotic solution (CaCl₂ 5 M) was circulated inside the fibres. The flux, the driving force, and the mass transfer coefficient were evaluated. A decrease of the water flux over time was observed and was attributed only to the decrease of the driving force, caused by the dilution of the osmotic solution. Using a surface area/feed volume ratio of 774 m²·m(-3), it is possible to reach a tea concentration of 40% (w/w) in 5 h, with a constant water flux and without losing the phenolic content a...
Membranes, 2016
Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfi... more Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications.
Journal of Membrane Science, 2010
International Journal of Biological Macromolecules, 2015
In this work, the solution properties of the bacterial fucose-rich polysaccharide, FucoPol, were ... more In this work, the solution properties of the bacterial fucose-rich polysaccharide, FucoPol, were studied. The effect of pH (3.5-10.0) and ionic strength (0.02-1.0 M NaCl) on the intrinsic viscosity and steady shear flow were evaluated using a central composite rotatable design of experiments and surface response methodology. FucoPol's intrinsic and apparent viscosities presented a quite low variation under a wide range of pH (3.5-8.0) and ionic strength (0.05-0.50 M NaCl) values. FucoPol produced viscous solutions with shear-thinning behavior at different polymer concentrations (0.2-1.2 wt.%). Flow curves were successfully described by the Cross model. The viscosity of the first Newtonian plateau varied from 0.01 to 2.47 Pa s for polymer concentrations from 0.2 to 1.2 wt.%, and the dependence of the estimated relaxation time with polymer concentration suggests a large degree of interaction between FucoPol molecules. Given the results obtained, FucoPol is proposed as thickening agent for applications in which stability of the apparent viscosity under pH and ionic strength variations is required.
The objective of this work is to develop model composite films based on commercial pectin and k-c... more The objective of this work is to develop model composite films based on commercial pectin and k-carrageen, containing mica particles as impermeable barriers, and to characterize them in terms of their hygroscopic and permeability to water vapour and gases (oxygen and carbon dioxide). The water adsorption capacity of the polymer/mica films seemed to be independent of the amount of mica added, showing a rather constant sorption coefficient. Regarding the water vapour permeability, a decrease was observed with the inclusion of mica, until a minimum value of 5.8 x 10 -11 mol/ (m s Pa) with 10% (dry weight) of mica particles added. As expected, these films are more permeable to water vapour than to O 2 and CO 2 . The CO 2 and O 2 permeability of the films is four orders of magnitude lower than their water vapour permeability and decreases with the increase of mica content in the film. The films presented good barrier properties to gases, and their water vapour and gas permeability was re...
Procedia Food Science, 2011
In this work the barrier properties of biodegradable films for food packaging using commercial pe... more In this work the barrier properties of biodegradable films for food packaging using commercial pectin and kcarrageenan and nanoclays organically modified were studied. Films (67% k-carrageenan) and different amounts of nanoclays (1, 5 and 10%) were prepared by casting. A pronounced decrease in the water vapour permeability with the higher driving force used (RH 92%-65%) is observed. It reduces about 35% of its initial value at 10% nanoclay content. The films permeability to carbon dioxide also reduces 50% for 1% nanoclay content. Films barrier properties may be further improved by enhancing the particles dispersion and exfoliation degree.
Journal of Membrane Science, 2013
Journal of Food Engineering, 2006
In this work, the osmotic evaporation (OE) and membrane distillation (MD) processes were compared... more In this work, the osmotic evaporation (OE) and membrane distillation (MD) processes were compared in terms of water flux and aroma retention. The concentration of a sucrose solution, used as a model fruit juice, was carried out in a hollow fibre membrane contactor. ...
Journal of Applied Polymer Science, 2013
Microbial polysaccharides are characterized by high molecular structure variability which transla... more Microbial polysaccharides are characterized by high molecular structure variability which translates into a wide range of different properties offering interesting opportunities for application in many different areas, including membrane-based products and processes. Due to their new or improved properties, microbial polysaccharides can replace plant, algae, and animal products, either in their traditional or in new applications. The main constraint to their wider use is the production costs that are still higher than that of other natural and synthetic polymers. The current applications of microbial polysaccharide membranes in medical, food, and industrial processes are outlined. The limitations still faced by these membranes and the requirements for obtaining innovative products and processes are also addressed.