Carla A M Portugal

New University of Lisbon, Lisboa, Lisbon, Portugal

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Publications (21)34.3 Total impact

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    ABSTRACT: The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell-scaffold interactions. The changes induced upon adsorption of two model proteins with different geometries, trypsin (globular conformation) and fibrinogen (rod-shaped conformation) on poly-L-lactic acid (PLLA) scaffolds with different surface topographies, flat, fibrous and surfaces with aligned nanogrooves, were assessed by fluorescence spectroscopy monitoring, using tryptophan as structural probe. Hence, maximum emission blue shift and the increase of fluorescence anisotropy observed after adsorption of globular and rod-like shaped proteins on surfaces with parallel nanogrooves were ascribed to more intense protein-surface interactions. Furthermore, the decrease of fluorescence anisotropy observed upon adsorption of proteins to scaffolds with fibrous morphology was more significant for rod-shaped proteins. This effect was associated to the ability of these proteins to adjust to curved surfaces. The additional unfolding of proteins induced upon adsorption on scaffolds with a fibrous morphology may be the reason for better cell attachment there, promoting an easier access of cell receptors to initially hidden protein regions (e.g. RGDS sequence), which are known to have a determinant role in cell attaching processes.
    Journal of biotechnology. 09/2014;
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    ABSTRACT: Magnetic Ionic Liquid (MILs), novel magnetic molecules that form "pure magnetic liquids," will follow the Ferrohydrodynamic Bernoulli Relationship. Based on recent literature, the modeling of this fluid system is an open issue and potentially controversial.
    Journal of Colloid and Interface Science 08/2014; 428:16-23. · 3.55 Impact Factor
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    ABSTRACT: a b s t r a c t Ionic liquids are widely under research due to their potential properties as solvents. The prediction of their physicochemical properties is an important strategy to achieve a better knowledge for further applications. The present work applies a group contribution method to estimate the viscosity at different tem-peratures of a new generation of ionic liquids, magnetic ionic liquids (MILs), which are comprised by anions containing transition metal complexes. These new substances have received a high interest due to their response at the presence of a magnetic field. In this study the magnetic ionic liquids are based on the phosphonium cation [P 66614 ] + with different chain lengths and on the magnetic anions: [GdCl 6 ] 3− , [MnCl 4 ] 2− , [FeCl 4 ] − and [CoCl 4 ] 2− . The database covers a wide range of temperature, 293.15–373.15 K, and viscosity 44–123 500 cP. The modelling estimations show a good agreement with the experimental results, presenting a mean percentage deviation of 7.64%. These results confirm the interest of this model for the estimation of viscosity and the influence of the temperature, which can be extended for a large variety of group combinations in magnetic ionic liquids leading to different applications.
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    ABSTRACT: It is presented a study of the molecular dynamics and of the viscosity in pure [Aliquat][Cl] ionic liquid and in a mixture of [Aliquat][Cl] with 1% (v/v) of [Aliquat][FeCl4]. The 1H spinlattice relaxation rate, R1, was measured by NMR relaxometry between 8 kHz and 300 MHz. In addition, the translation self-diffusion coefficient, D, was measured by pulse field gradient NMR. The ILs' viscosity was measured as a function of an applied magnetic field, B, and it was found that IL mixture's viscosity decreased with increasing B, whereas the [Aliquat][Cl] viscosity is independent of B. All experimental results were analyzed taking into account the viscosity's magnetic field dependence, assuming a modified Stokes-Einstein diffusion/viscosity relation. The main difference between the relaxation mechanisms responsible for R1 in the two IL systems is related with the additional paramagnetic relaxation contribution associated to the 1H spins - [FeCl4] paramagnetic moments' interactions. Cross-relaxation cusps in the R1 dispersion, associated with 35Cl and 1H nuclear spins in the IL systems, were detected. The R1 model considered was successfully fitted to the experimental results and it was possible to estimate the value of D at zero field in the case of the IL mixture which was consistent with the values of D measured at 7 T and 14.1 T and with the magnetic field dependence estimated from the viscosity measurements. It was observed that a small concentration of [Aliquat][FeCl4] in the [Aliquat][Cl] was enough to produce a "super-paramagnetic"-like effect and to change the IL mixture's molecular dynamics and viscosity and to allow for their control with an external magnetic field.
    The Journal of Physical Chemistry B 08/2013; · 3.61 Impact Factor
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    ABSTRACT: This work aims at studying the influence of magnetic field on the intrinsic physicochemical (e.g. rheological behavior, solubility [1]) and structural properties of a novel class of magnetic responsive ionic liquids - MILs and the potential impact of their magnetic behavior on the diffusion mechanisms of solvents and solutes through MILs liquid membranes. The existence of ionic liquids exhibiting the ability to switch reversibly their physicochemical properties and structural organization of their ionic network by changing the conditions (intensity and directional vector) of the applied magnetic field is particularly promising regarding the design of novel membrane based separation processes e.g. magnetic responsive supported liquid membranes. These membranes are expected to allow for an adjustable permeability and/or selectivity, contributing consequently for an improved transport of solutes through a fine tuning of the magnetic field conditions. The molecular dynamics of MILs was assessed through proton Nuclear Magnetic Resonance (1H NMR) relaxometry. This technique provided information about the molecular dynamics of MILs ionic network in the broad range of magnetic fields (B=2pnL/g), namely between 0.2 mT and 7 T. The results obtained show the existence of a specific relaxation mechanism associated with the presence of the magnetic anions [FeCl4], which is observed in the MHz range of Larmor frequencies of the spin-lattice relaxation time (T1) dispersion (Fig. 1a). Viscosimetry analysis performed in the magnetic field range 0-2T, revealed that the MILs viscosity decreases with the increase of the magnetic field (Fig. 1b). Together, resonance relaxometry and viscosimetry analysis allowed for the determination of the evolution of MILs self-diffusion coefficients with the magnetic field as well as for the establishment of a comprehensive correlation between the magnetic induced structural rearrangements and the MILs physicochemical and self-diffusional properties. Figure1. a) 1H-NMR spin-lattice-relaxation results, as a function of the frequency nL =gB/2p, for the magnetic ionic liquid AliquatFeCl4 and for the analog non-magnetic ionic liquid AliquatCl; b) Viscosity dependence with magnetic field for the MILs. Gas transport studies through supported liquid membranes with immobilized MILs were performed at magnetic field intensities up to 1.5 T, in order to evaluate the impact of magnetic sensitivity of MILs viscosity and self-diffusion on membrane permeability and selectivity [2]. The results obtained show that the membrane selectivity is not much influenced by the magnetic field. However, the increase of the magnetic field leads to the increase of membrane permeability to the different gases (CO2, N2 and air) tested. Therefore, it is possible to conclude that the magnetic responsive supported liquid membranes designed in this work allowed for a non-invasive modulation of gas permeability by adjustment of the external magnetic field intensity. References [1] S. Lee, S. Ha, H. Jin, C. You and Y. Koo, Magnetic behavior of mixture of magnetic ionic liquid bmim[FeCl4] and water, J. Applied. Physics 101 (2007) 102. [2] E. Santos, J.Albo, C.I.Daniel, C.A.M.Portugal, J.G.Crespo, A.Irabien. Permeability modulation of Supported Magnetic Ionic Liquid Membranes (SMILMs) by an external magnetic field. Journal of Membrane Science 430 (2013) 56. Acknowledgements The authors gratefully acknowledge the financial support from the European Research Action Network-ERANET, ERA-CHEM/0001/2008 Project (Portugal) and Project EUI 2008- 03857 (Spain). Carla Daniel acknowledges the financial support of FCT-MCTES through the PhD grant SFRH/BD/81552/2011.
    North American Membrane Society Meeting 2013; 06/2013
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    ABSTRACT: Ionic liquids are widely under research due to their potential properties as solvents. The prediction of their physicochemical properties is an important strategy to achieve a better knowledge for further applications. The present work applies a group contribution method to estimate the viscosity at different temperatures of a new generation of ionic liquids, magnetic ionic liquids (MILs), which are comprised by anions containing transition metal complexes. These new substances have received a high interest due to their response at the presence of a magnetic field. In this study the magnetic ionic liquids are based on the phosphonium cation [P66614]+ with different chain lengths and on the magnetic anions: [GdCl6]3−, [MnCl4]2−, [FeCl4]− and [CoCl4]2−. The database covers a wide range of temperature, 293.15–373.15 K, and viscosity 44–123 500 cP. The modelling estimations show a good agreement with the experimental results, presenting a mean percentage deviation of 7.64%. These results confirm the interest of this model for the estimation of viscosity and the influence of the temperature, which can be extended for a large variety of group combinations in magnetic ionic liquids leading to different applications.
    Fluid Phase Equilibria 01/2013; 360:29–35. · 2.38 Impact Factor
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    ABSTRACT: A combined fluorescence analysis, involving the use of steady-state fluorescence and fluorescence anisotropy was used, allowing eliciting information about the structural changes induced on trypsin after exposure to membrane surfaces with diverse chemistry, designed through a layer-by-layer methodology. Using this monitoring strategy it was possible to understand the influence of the surface chemistry on the structural characteristics of the attached proteins and how they relate to changes of their activity resulting from the adsorption process. This knowledge may be used to direct the development of surfaces with suitable chemistry, leading enzymatic-based processes with improved performance. The results obtained show clearly that trypsin exposed to different membrane surfaces, changes its conformation, either if it adsorbs to the membrane or if it remains in solution. A significant loss of enzymatic activity was observed upon the adsorption process, for the adsorbed and non-adsorbed protein. This loss of the trypsin activity was correlated with the presence of molecular unfolding events that mediate trypsin-membrane surface interactions and the decrease of the molecular mobility of the adsorbed trypsin, which was shown to be dependent on the chemical characteristics of the membrane surface. Changes on the selectivity of the adsorbed trypsin were also observed, and may be ruled by the strength of the enzyme-surface interactions established.
    Enzyme and microbial technology. 12/2012; 51(6-7):325-33.
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    ABSTRACT: In the present study, the performance of a membrane bioreactor (MBR) was modelled using a hybrid approach based on the activated sludge model number 3 (ASM3) combined with projection to latent structures (PLS) to predict the residuals of the ASM. The application of ASM to MBRs requires frequent re-calibration to adjust the model to variations in influent characteristics, determined through time-consuming analysis and batch tests. Considering this problem, the objective of this study was to improve ASM prediction ability with minimal additional monitoring effort. Hybrid models were developed to predict three MBR performance parameters: mixed liquor suspended solids (MLSS), COD in the permeate (CODp) and nitrite and nitrate concentration in the permeate (NOxp). For PLS modelling of ASM residuals three input strategies were used: (1) analytic and operating data; (2) operating data plus 2D fluorescence spectroscopy; (3) all the data. The first input strategy improved ASM prediction of the three selected outputs, and highlighted the lack of detailed and real-time information from wastewater and operating parameters in the ASM used in this study. In the second input strategy, the incorporation of updated data from 2D fluorescence spectroscopy resulted on better model fitting than in the first input strategy, for all the output parameters studied. Through the hybrid modelling approach it was possible to significantly improve the ASM predictions in real-time using 2D fluorescence measurements and other relevant parameters acquired on-line, without requiring further laboratory analysis. Furthermore, the third input strategy, incorporating all the collected data, did not significantly improve the prediction of the outputs beyond the second strategy. This shows that 2D fluorescence spectroscopy is a comprehensive monitoring tool, able to capture on-line the required information to complement, through hybrid modelling, the mechanistic information described by an ASM.
    Journal of Biotechnology 07/2012; · 3.18 Impact Factor
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    ABSTRACT: This work presents the development of multivariate statistically-based models for monitoring several key performance parameters of membrane bioreactors (MBR) for wastewater treatment. This non-mechanistic approach enabled the deconvolution of 2D fluorescence spectroscopy data, a powerful technique that has previously been shown to capture important information regarding MBR performance. Projection to latent structure (PLS) modelling was used to integrate 2D fluorescence data, after compression through parallel factor analysis (PARAFAC), with operation and analytical data to describe an MBR fouling indicator (transmembrane pressure, TMP), five descriptors of the effluent quality (total COD, soluble COD, concentration of nitrite and nitrate, total nitrogen and total phosphorus in the permeate) and the biomass concentration in the bioreactor (MLSS). A multilinear correlation was successfully established for TMP, CODtp and CODsp, whereas the optimised models for the remaining outputs included quadratic and interaction terms of the compressed 2D fluorescence matrices. Additionally, the coefficients of the optimised models revealed important contributions of some of the input parameters to the modelled outputs. This work demonstrates the applicability of 2D fluorescence and statistically-based models to simultaneously monitor multiple key MBR performance parameters with minimal analytical effort. This is a promising approach to facilitate the implementation of MBR technology for wastewater treatment.
    Water Research 04/2012; 46(11):3623-36. · 4.66 Impact Factor
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    ABSTRACT: BACKGROUND: The use of two-dimensional (2D) fluorescence for monitoring complex biological systems requires careful assessment of the effect of chemical species present, which may be fluorescent and/or may interfere with the fluorescence response of target fluorophores. Given the complexity of fluorescence data (excitation emission matrices—EEMs), the challenge is how to recover the information embedded into those EEMs that can be related quantitatively with the observed performance of the biological processes under study.RESULTS: This work shows clearly that interference effects (such as quenching and inner filter effects) occur due to the presence of multiple species in complex biological media, such as natural water matrices, wastewaters and activated sludge. A statistical multivariate analysis is proposed to recover quantitative information from 2D fluorescence data, correlating EEMs with the observed performance. A selected case study is discussed, where 2D fluorescence spectra obtained from the effluent of a membrane bioreactor were compressed using PARAFAC and successfully correlated with the effluent chemical oxygen demand, using projection to latent structures modelling.CONCLUSION: This study demonstrates the potential of using 2D fluorescence spectroscopy as a status fingerprint. Additionally, it is shown how statistical multivariate data analysis can be used to correlate EEMs with selected performance parameters for monitoring of biological systems. Copyright © 2011 Society of Chemical Industry
    Journal of Chemical Technology & Biotechnology 03/2011; 86(7):985 - 992. · 2.50 Impact Factor
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    ABSTRACT: An important setback for a wider use of membrane processes in industry is fouling, caused by aggregation of biomolecules at membrane surface and pores. Two important approaches to reduce this effect are the use of chemical cleaning procedures and the functionalisation of the membrane surface. However, both processes may lead to membrane degradation and structure alteration due to free radical formation or radical interaction with membrane polymer chains. In this work, electron paramagnetic resonance (EPR) was used to evaluate and quantify radical formation in both chemical cleaning and membrane functionalisation by UV grafting, allowing for a better understanding of free radical formation processes and their influence on membrane characteristics. Studies under different cleaning and grafting conditions, such as, cleaning agent concentration and pH, light intensity and irradiation were also performed showing the potential of EPR as a technique for monitoring both procedures. The information provided by EPR may contribute significantly to the development of new cleaning strategies which minimise the effect of membrane ageing and to the implementation of new and more efficient grafting procedures.
    Desalination and water treatment 01/2011; 27:141. · 0.85 Impact Factor
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    ABSTRACT: The application of membrane bioreactors (MBR) for wastewater treatment is growing worldwide due to their compactness and high effluent quality. However, membrane fouling, mostly associated to biological products, can reduce MBR performance. Therefore, it is important to monitor MBRs as close to real-time as possible to accelerate control actions for maximal biological and membrane performance. 2D-fluorescence spectroscopy is a promising on-line tool to simultaneously monitor wastewater treatment efficiency and the formation of potential biological fouling agents. In this study, 2D-fluorescence data obtained from the wastewater and the permeate of a MBR was successfully modelled using projection to latent structures (PLS) to monitor variations in the influent and effluent total chemical oxygen demand (COD). Analysis of the results also indicated that humic acids and proteins highly contributed to the measured COD in both streams. Nevertheless, this approach was not valid for other performance parameters of the MBR system (such as influent and effluent ammonia and phosphorus), which is usually characterised through a high number of analytical and operating parameters. Principal component analysis (PCA) was thus used to find possible correlations between these parameters, in an attempt to reduce the analytical effort required for full MBR characterisation and to reduce the time frame necessary to obtain monitoring results. The 3 first principal components, capturing 57% of the variance, indicated and confirmed expected relationships between the assessed parameters. However, this approach alone could not provide robust enough correlations to enable the elimination of parameters for process description (PCA loadings ≤ 0.5). Nevertheless, it is possible that the information captured by 2D-fluorescence spectroscopy could replace some of the analytical and operating parameters, since this technique was able to successfully describe influent and effluent total COD. It is thus proposed that combined modelling of 2D-fluorescence data and selected performance/operating parameters should be further explored for efficient MBR monitoring aiming at rapid process control.
    Water Science & Technology 01/2011; 63(7):1381-8. · 1.10 Impact Factor
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    ABSTRACT: In this work a membrane bioreactor (MBR) system for wastewater treatment is monitored using 2D-fluorescence spectroscopy as a fingerprint of the system status. Fluorescence maps were correlated with the operational parameters of the MBR using non-mechanistic methods, such as principal component analysis (PCA) and projection to latent structures (PLS), for process monitoring and optimisation. The 2D-fluorescence technique was used as a tool for monitoring the performance of a pilot MBR. It was found that the combination of the 2Dfluorescence data with selected operational and performance variables captures additional information about the biological system status and substantially enhances MBR modeling and performance prediction.
    Proceedings of the Water Environment Federation. 12/2008;
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    ABSTRACT: The main objective of the present study was to investigate the use of in situ 2D fluorometry for monitoring key bioprocess variables in mammalian cell cultures, namely the concentration of viable cells and the concentration of recombinant proteins. All studies were conducted using a recombinant Baby Hamster Kidney (BHK) cell line expressing a fusion glycoprotein IgG1-IL2 cultured in batch and fed-batch modes. It was observed that the intensity of fluorescence signals in the excitation/emission wavelength range of amino acids, vitamins and NAD(P)H changed along culture time, although the dynamics of single fluorophors could not be correlated with the dynamics of the target state variables. Therefore, multivariate chemometric modeling was adopted as a calibration methodology. 2D fluorometry produced large volumes of redundant spectral data, which were first filtered by principal components analysis (PCA). Then, a partial least squares (PLS) regression was applied to correlate the reduced fluorescence maps with the target state variables. Two validation strategies were used to evaluate the predictive capacity of the developed PLS models. Accurate estimations of viable cells density (r(2) = 0.95; 99.2% of variance captured in the training set; r(2) = 0.91; 97.7% of variance captured in the validation set) and of glycoprotein concentration (r(2) = 0.99 and 99.7% of variance captured in the training set; r(2) = 0.99 and 99.3% of variance captured in the validation set) were obtained over a wide range of reactor operation conditions. The results presented herein confirm that 2D fluorometry constitutes a reliable methodology for on-line monitoring of viable cells and recombinant protein concentrations in mammalian cell cultures.
    Biotechnology and Bioengineering 10/2008; 102(4):1098-106. · 4.16 Impact Factor
  • Carla A.M. Portugal, J.C. Lima, João G. Crespo
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    ABSTRACT: This work aims for determining the impact of different environmental conditions, such as pH, ionic strength (salt concentration) and the chemistry of the membrane surface (hydrophilic/hydrophobic character) on the structure of permeating proteins after ultrafiltration. In the permeation experiments reported in this paper, different solutions of a model protein – β-lactoglobulin – at pH 3, 5 and 8 and salt concentrations of 1, 10 and 100 mM were processed with membranes of different molecular weight cut-off (10 and 30 kDa) and materials (regenerated cellulose—RC, and polyethersulfone—PES).The analysis of the structural alterations induced in the permeating molecules of β-lactoglobulin after ultrafiltration was performed using a methodology that combines the use of complementary fluorescence techniques: steady-state fluorescence and steady-state fluorescence anisotropy.From the results obtained it was concluded that permeation performed under pH values below the isoelectric point of β-lactoglobulin, at high salt concentrations and using membranes with hydrophobic character allows for minimization of the impact of the membrane processing in the structure of β-lactoglobulin.
    Journal of Membrane Science. 01/2008;
  • Carla A.M. Portugal, João G. Crespo, J.C. Lima
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    ABSTRACT: This work aims to identify of non-reversible structural changes induced in β-lactoglobulin by permeation through porous ultrafiltration membranes. The evaluation of these structural changes is performed using a fluorescence methodology, which combines the use of three different, complementary, fluorescence techniques: steady-state fluorescence, picosecond time-resolved fluorescence and steady-state fluorescence anisotropy. The identification of the nature of the structural changes induced upon permeation is possible through comparison of the fluorescence responses obtained for β-lactoglobulin solutions collected after permeation (permeates and retentates) with those induced by chemical (addition of Guanidine hydrochloride, GndHCl) and thermal denaturation of β-lactoglobulin.The fluorescence approach used allowed to identify irreversible losses of structural integrity of β-lactoglobulin in the permeates, while β-lactoglobulin retentates seemed to be unaffected by the ultrafiltration process.The mechanisms that regulate the structural alterations of β-lactoglobulin and the magnitude of these alterations depend on the protein to membrane pore size ratio, λ, being more substantial at higher λ (severe pore constriction). Under these conditions (permeation with a 10 kDa membrane) the structural changes induced in the proteins are dictated by the high shear stress at the membrane pore walls. The increase of the membrane cut-off (30 kDa membrane) induces a decrease in the magnitude of the shear stress and the effect of protein–membrane chemical interactions becomes noticeable.
    Journal of Membrane Science. 08/2007;
  • Carla A M Portugal, João G Crespo, J C Lima
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    ABSTRACT: Picosecond time-resolved fluorescence, together with the addition of quenching agents, was employed to discriminate the fluorescence contributions of the two tryptophans of beta-lactoglobulin (Trp19 and Trp61) to the fluorescence decays of the protein. The fluorescence decays of beta-lactoglobulin at pH 3, 5 and 8 are best fitted using sums of three exponentials and show a dominant contribution (98%) of the components associated with the buried Trp19, which decays according to a double exponential function. The addition of acrylamide (0.05 M) causes an increase of the decay times associated with Trp19. This effect is observed at all pH values studied, but the effect is stronger at pH 3 and pH 5, than at pH 8. The unexpected increase of the decay times of Trp19 and the variation of the respective amplitudes were rationalized in terms of alterations of Trp19 mobility. The hindrance of Trp19 upon acrylamide binding was also monitored and supported by fluorescence anisotropy measurements.
    Journal of Photochemistry and Photobiology B Biology 03/2006; 82(2):117-26. · 3.11 Impact Factor
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    Carla A.M. Portugal, J.C. Lima, João G. Crespo
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    ABSTRACT: Changes in the molecular structure of horseradish peroxidase (HRP-4C) induced by membrane ultrafiltration, as well as its impact on the enzymatic activity, were monitored using three complementary fluorescence techniques: steady-state fluorescence, fluorescence anisotropy and picosecond time-resolved fluorescence. Ultrafiltration experiments were performed using membranes of polyethersulfone (PES) with 30 and 100 kDa and membranes of regenerated cellulose (RC) with 10 and 30 kDa.The results obtained clearly shows HRP-4C structural changes during ultrafiltration, which were essentially controlled by hydrophobic and electrostatic protein–membrane interactions. The structural changes observed depend on the affinity of the membrane material to ions, such as Fe3+ and Ca2+, which have a substantial structural and functional relevance to this enzyme. Additionally, it was found that the impact of the ultrafiltration process on the enzymatic activity was a direct consequence of the depletion of iron from the protein structure, causing irreversible structural alterations on HRP-4C, and thus inducing severe changes in its enzymatic activity.
    Journal of Membrane Science. 01/2006;
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    ABSTRACT: This work aims to present a comprehensive study about the macroscopic characteristics of globular vegetable proteins, in terms of their gelling ability, by understanding their molecular behaviour, when submitted to a thermal gelling process. The gels of soy, pea and lupin proteins were characterized by rheological techniques. Gelation kinetics, mechanical spectra, as well as the texture of these gels were analyzed and compared. Additionally, capillary viscometry, steady-state fluorescence and fluorescence anisotropy were used to monitor the structural changes induced by the thermal denaturation, which constitutes the main condition for the formation of a gel structure. Based on these techniques it was possible to establish a relationship between the gelling ability of each protein isolate and their structural resistance to thermal unfolding, enabling us to explain the weakest and the strongest gelling ability observed for lupin and soy proteins isolates, respectively.
    International Journal of Biological Macromolecules 09/2005; 36(3):135-43. · 2.60 Impact Factor
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    ABSTRACT: This work aims to present a comprehensive study about the macroscopic characteristics of globular vegetable proteins, in terms of their gelling ability, by understanding their molecular behaviour, when submitted to a thermal gelling process. The gels of soy, pea and lupin proteins were characterized by rheological techniques. Gelation kinetics, mechanical spectra, as well as the texture of these gels were analyzed and compared. Additionally, capillary viscometry, steady-state fluorescence and fluorescence anisotropy were used to monitor the structural changes induced by the thermal denaturation, which constitutes the main condition for the formation of a gel structure. Based on these techniques it was possible to establish a relationship between the gelling ability of each protein isolate and their structural resistance to thermal unfolding, enabling us to explain the weakest and the strongest gelling ability observed for lupin and soy proteins isolates, respectively.

Publication Stats

58 Citations
34.30 Total Impact Points

Institutions

  • 2005–2014
    • New University of Lisbon
      • Faculty of Sciences and Technology
      Lisboa, Lisbon, Portugal
  • 2012
    • French National Centre for Scientific Research
      • Institut Européen des Membranes (IEM)
      Montpelhièr, Languedoc-Roussillon, France
  • 2011
    • Instituto de Biologia Experimental e Tecnológica IBET
      Quinta da Anjo, Setúbal, Portugal