Publications

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    ABSTRACT: Hollow multilayer nanocapsules were successfully prepared through layer-by-layer assembly of two bioactive polysaccharides, chitosan and fucoidan. The stepwise adsorption of 10 chitosan/fucoidan layers and the consequent formation of a multilayer film on polystyrene nanoparticles (used as templates) were followed through ζ-potential measurement and the removal of the polystyrene core was confirmed by FTIR analysis. The chitosan/fucoidan nanocapsules morphology and size were evaluated by SEM and TEM, which showed that after the core removal, the nanocapsules maintained their spherical shape and a decrease of size occurred. A cationic bioactive compound, poly-L-lysine (PLL), was chosen to evaluate the loading and release behaviour of the nanocapsules. The chitosan/fucoidan nanocapsules showed a good capacity for the encapsulation and loading of PLL, which shows to be influenced by the initial PLL concentration and the method of encapsulation used. The results of fitting the linear superimposition model to the experimental data of PLL release suggest an anomalous behaviour, with one main polymer relaxation. The PLL release was found to be pH-dependent: at pH 2 relaxation is the governing phenomenon and at pH 7 Fick's diffusion is the main mechanism of PLL release. Chitosan/fucoidan nanocapsules is a promising delivery system for water soluble bioactive compounds, such as PLL, showing a great potential of application in food and pharmaceutical industries
    Carbohydrate Polymers 01/2015; 115:1–9. · 3.92 Impact Factor
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    ABSTRACT: The characterization of several commercial dextrins and the analysis of the potential of dextrin derived hydrogels for biomedical applications were performed in this work. The structural characterization of dextrins allowed the determination of the polymerization and branching degrees, which ranged from 6 to 17 glucose residues and 2 to 13%, respectively. Tackidex, a medical grade dextrin was choosen for further characterization. The combination of hydrogel with a dextrin nanogel and urinary bladder matrix was achieved without compromising the mechanical properties or microstructure. The encapsulation of cells, preserving its viability, confirms the biocompatibility of the injectable hydrogels, which have therefore great potential for biomedical applications.
    Carbohydrate Polymers 12/2014; 114C:458-466. · 3.92 Impact Factor
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    ABSTRACT: Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension.
    Carbohydrate Polymers 11/2014; 113C:490-499. · 3.92 Impact Factor
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    ABSTRACT: Alterations in muscle mitochondrial bioenergetics during cancer cachexia were previously suggested; however, the underlying mechanisms are not known. So, the goal of this study was to evaluate mitochondrial phospholipid remodeling in cancer-related muscle wasting and its repercussions to respiratory chain activity and fiber susceptibility to apoptosis. An animal model of urothelial carcinoma induced by exposition to N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) and characterized by significant body weight loss due to skeletal muscle mass decrease was used. Morphological evidences of muscle atrophy were associated to decreased respiratory chain activity and increased expression of mitochondrial UCP3, which altogether highlight the lower ability of wasted muscle to produce ATP. Lipidomic analysis of isolated mitochondria revealed a significant decrease of phosphatidic acid, phosphatidylglycerol and cardiolipin in BBN mitochondria, counteracted by increased phosphatidylcholine levels. Besides the impact on membrane fluidity, this phospholipid remodeling seems to justify, at least in part, the lower oxidative phosphorylation activity observed in mitochondria from wasted muscle and their increased susceptibility to apoptosis. Curiously, no evidences of lipid peroxidation were observed but proteins from BBN mitochondria, particularly the metabolic ones, seem more prone to carbonylation with the consequent implications in mitochondria functionality. In overall, data suggest that bladder cancer negatively impacts skeletal muscle activity specifically by affecting mitochondrial phospholipid dynamics and its interaction with proteins, ultimately leading to the dysfunction of this organelle. The regulation of phospholipid biosynthetic pathways might be seen as potential therapeutic targets for the management of cancer-related muscle wasting.
    Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 06/2014; · 4.50 Impact Factor
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    ABSTRACT: The antioxidant activity of Pinus pinaster seedlings originating from two contrasting maternal environments and inoculated with the fungal pathogen Fusarium circinatum was examined. The antioxidant activity related positively to the stem necrosis caused by the pathogen (p = 0.005), but this relationship differed significantly between maternal environments (p ≤ 0.002). Seedlings from mother trees grown under a favourable environment expressed a more variable antioxidant activity to F. circinatum than seedlings from mother trees grown in a less favourable environment. Antioxidant activity ranging from 80 to 100% resulted in shorter necrosis in seedlings from the favourable maternal environment than in seedlings from the unfavourable environment. Maternal effects caused shifts in the relationship between antioxidant activity and necrosis in offspring, and significantly modified the individual plant capacity for antioxidant response on pathogen penetration.
    Forest Pathology 04/2014; · 1.49 Impact Factor
  • Scientia Agricola 01/2014; 71(4):331-336. · 0.92 Impact Factor
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    ABSTRACT: Carbohydrate differences in offspring as a consequence of maternal effects explain transgenerational tree-pathogen interactions. The expression of disease is increasingly recognised as being influenced by maternal effects, given that environmental conditions experienced by mother trees affect tolerance in offspring. It is hypothesised that plant carbohydrates could mediate transgenerational tree-pathogen interactions. The carbohydrate content of Pinus pinaster seedlings obtained from two contrasting maternal environments was studied and seedlings from the two environments were challenged with Fusarium circinatum. The representative mid-infrared spectra of samples in the range of the carbohydrates diagnosed higher proportion of methylesterified pectic polysaccharides and lower proportion of nonesterified pectic polysaccharides for inoculated than for control seedlings. Total carbohydrate content of seedlings from the unfavourable environment did not differ much from total carbohydrate content of seedlings from the favourable maternal environment. However, glucose was 13 % higher and uronic acids 11 % lower in seedlings from the favourable environment after inoculation in comparison to seedlings from the unfavourable maternal environment which had their carbohydrate contents unaltered after inoculation. It is concluded that plant carbohydrates mediate transgenerational tree-pathogen interactions.
    Trees 01/2014; · 1.87 Impact Factor
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    ABSTRACT: The application of high hydrostatic pressure (HHP) in winemaking for substitution of the use of sulphur dioxide is still at a very early stage of development, since knowledge about the effect on physicochemical and sensorial characteristics of the wine during storage is very scarce. In this work, the evolution of colour, antioxidant activity and total phenolic compounds of SO2-free red wines treated by HHP and aged in bottles was followed for 12months. The pressurised wines were compared with wine samples prepared with addition of 40ppm of SO2 and without any of these two treatments. After 12months, the pressurised wines presented higher values of CIELab parameters (a(∗), b(∗), and L(∗)) and a lower monomeric anthocyanin content (45-61%) when compared to the unpressurised ones. The pressurised wines showed also a better global sensorial assessment, with the pressure treatments imparting aged-like characteristics to the wines. The wine deposits of pressurised wines had higher total phenolic content, namely proanthocyanidins (3- to 10-fold). The results demonstrate that HHP can influence long term red wine physicochemical and sensorial characteristics, hypothesised to be due to an increase of condensation reactions of phenolic compounds, forming compounds with higher degree of polymerisation that became insoluble in wine along storage.
    Food Chemistry 12/2013; 141(3):2558-66. · 3.26 Impact Factor
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    ABSTRACT: Lipid homeostasis in liver is known to be altered with diabetes mellitus, ultimately leading to liver damage and related complications. The present work aimed to evaluate changes in the liver phospholipid profile after four months of uncontrolled hyperglycemia. Twenty Wistar rats were divided into two groups: control and streptozotocin-treated (T1DM). After four months, animals were sacrificed and morphological characterization of liver was performed and related with serum markers of hepatic damage. Lipid extracts were obtained from liver and phospholipid (PL) classes were quantified. Lipid molecular species were determined by LC-MS and LC-MS/MS, and fatty acids by GC-MS. Concomitantly with signs of hepatic damage we found variations in the relative amount of phospholipid classes in T1DM, characterized by a decrease in PLs with choline head group, and by an increase in the relative content of other PL classes. A remodeling in PL fatty acyl chains was observed in T1DM liver, with a similar pattern to all the PL classes, and consisting in the reduction of 16:0 and an increase of 18:0 and 18:2 acyl chains. The observed changes in T1DM lipid profile may contribute to the altered membrane properties underlying hepatic damage, worsening the metabolic alterations that characterize T1DM.
    Archives of Biochemistry and Biophysics 08/2013; · 3.04 Impact Factor
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    ABSTRACT: The impact of high hydrostatic pressure (HHP) treatments on physicochemical characteristics of sulphur dioxide-free white wines was studied during one year of bottle storage. For this purpose, a white wine was produced without the addition of sulphur dioxide (SO2) and was pressurized at two pressure conditions, 500 and 425 MPa, for 5 min at 20 °C. A wine with 40 ppm of SO2 and a wine with no preservation treatment were used as controls. Pressurized wines showed, after one year of storage, a more brownish colour (higher a* and b* values and lower L*) and a slightly lower antioxidant activity and total content of phenolic compounds compared to the unpressurized wines (wine with SO2 and wine without any treatment). These results, together with the lower content of free amino acids (e.g 87% less of serine) and higher content of furans (e.g 10 fold higher of 2-furfural), presented in the pressurized wines after nine months of storage, lead to propose an effect of HHP treatments in the acceleration of Maillard reactions occurring during the wine storage period. Sensorial analysis showed that the pressurized wines presented a higher cooked fruit aroma and lower fruity and floral aromas than the unpressurized wines.
    Innovative Food Science & Emerging Technologies 07/2013; · 2.25 Impact Factor
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    ABSTRACT: A reversed-phase high-performance liquid chromatographic method with fluorometric detection is proposed for the simultaneous determination of different classes of neutral sugars, such as hexoses (galactose, glucose and mannose), pentoses (arabinose and xylose), deoxy-hexoses (fucose and rhamnose), as well as acidic sugars (galacturonic and glucuronic acids). The separation is carried out on a hydrophilic end capped C18 column following a pre-column derivatization with p-aminobenzoic acid. The fluorometric detection of the derivatives has shown a strong dependency with the mobile phase pH. The performance of the proposed methodology was evaluated and the prerequisites of linearity (r-value > 0.999), precision (intra-day CV < 6 % and inter-day CV < 11 %) and recovery (between 77 ± 7 and 103 ± 3 %) were satisfied. To our knowledge, the obtained values of limit of detection for neutral sugars (within the range 6.1–28 μg L−1) are the lowest reported using this derivatizing agent. In order to better judge the methodology presented herein, neutral sugars of a pectin-rich orange extract were also analysed by the conventionally used GC-FID (gas-chromatography with flame ionization detector) method of alditol acetate derivatives. A statistical test (paired t test) has proved that no significant differences (α = 0.05) were observed between these two methods.
    Chromatographia 07/2013; 76(17-18). · 1.37 Impact Factor
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    ABSTRACT: We carboxymethylated ulvan, extracted from the green algae Ulva lactuca, and chitosan, extracted from Loligo forbesis squid-pen, yielding polysaccharides with an average degree of substitution of ∼98% (carboxymethyl ulvan, CMU) and ∼87% (carboxymethyl chitosan, N,O-CMC). The carboxymethylation was confirmed by FTIR and quantified by conductimetric titration and (1)H NMR. The average molecular weight increased with the carboxymethylation (chitosan: Mn 145→296 kDa and Mw 227→416 kDa; ulvan: Mn 139→261 kDa and Mw 368→640 kDa) indicating successful chemical modifications. Mixtures of the modified polysaccharides were tested in the formulation of polyacrylic acid-free glass-ionomer bone cements. Mechanical and in vitro bioactivity tests indicate that the inclusion of CMU in the cement formulation, i.e. 0.50:0.50 N,O-CMC:CMU, enhances its mechanical performance (compressive strength of 52.4 ± 8.0 MPa and modulus of 2.3 ± 0.3 GPa), generates non-cytotoxic cements and induces the diffusion of Ca and/or P-based moieties from the surface to the bulk of the cements.
    Acta biomaterialia 06/2013; · 5.68 Impact Factor
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    ABSTRACT: Pitch canker disease is caused by Fusarium circinatum, a quarantine fungus in Europe with great virulence on several Pinus species. Susceptibility of Pinus pinaster to F. circinatum fungus has generated severe economic impact in nurseries of northern Spain. It is known that the maternal environment of P. pinaster significantly influences the resistance of their offspring to F. circinatum. To be protected from a wide variety of plant pathogens, plants have developed a complex set of defence mechanisms. Particularly, plant carbohydrates play an essential role during the pathogenesis of fungal diseases and plant antioxidant activity controls reactive oxygen species production during stress to protect themselves against oxidative damage. This study aims to evaluate the extent to which carbohydrates and antioxidant activity of P. pinaster originating from contrasting maternal environments could influence disease susceptibility of seedlings to F. circinatum. Seeds originating from the same clone but collected from two P. pinaster seed orchards located in Galicia (NW Spain) having identical genetic material and design but contrasting site qualities were selected. A total of 144 seeds, comprising 2 orchards × 3 ramets × 2 cones × 12 replicates were used. A randomised complete block design with seedlings growing in the same greenhouse was established. When plants were about 1.5 years old, seedlings were inoculated or not with F. circinatum. Four weeks after inoculation, necrosis length of inoculated and control seedlings were measured and all seedlings were harvested and samples removed. Samples consisting of a 3 cm stem segment below the inoculation point were immediately frozen in liquid N2 and stored at -80ºC until analysis. Changes in plant carbohydrates were assessed quantitatively by conventional techniques of gas chromatography and spectrophotometry, and qualitatively by Fourier transform-infrared (FT-IR) spectroscopy in association with chemometrics. Antioxidant activity was measured according to the method described in [1]. Total carbohydrate content was similar in seedlings from the unfavourable and favourable maternal environments and in non-inoculated and inoculated seedlings (P>0.05). However, seedlings from the favourable maternal environment significantly increased 13% their glucose content due to inoculation and reduced 11% their uronic acids content due to inoculation (P=0.045), while seedlings from the unfavourable maternal environment had their carbohydrate contents unaltered with the inoculation treatment. The antioxidant activity increased with the necrosis caused by the pathogen (P = 0.005) and differed between maternal environments (P < 0.001). Seedlings from the favourable maternal environment showed less antioxidant activity for a given lesion in comparison with seedlings from the unfavourable maternal environment. It is concluded that changes in carbohydrate content and antioxidant activity of P. pinaster seedlings after F. circinatum challenge were mediated by maternal effects, in the way that inoculated plants from the favourable maternal environment enhanced glucose and decreased uronic acids, and showed a more efficient antioxidant system in comparison with plants from the unfavourable maternal environment.
    IUFRO 2013 WP 7.02.02 Foliage Shoot and Stems Diseases: Biosecurity in Natural Forests and Plantations, Genomics and Biotechnology for Biosecurity and Forestry; 05/2013
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    ABSTRACT: The use of chitosan films has been limited due to their high degradability in aqueous acidic media. In order to produce chitosan films with high antioxidant activity and insoluble in acid solutions caffeic acid was grafted to chitosan by a radical mechanism using ammonium cerium (IV) nitrate (60mM). Genipin was used as cross-linker. This methodology originated films with 80% higher antioxidant activity than the pristine film. Also, these films only lost 11% of their mass upon seven days immersion into an aqueous solution at pH 3.5 under stirring. The films surface wettability (contact angle 105°), mechanical properties (68MPa of tensile strength and 4% of elongation at break), and thermal stability for temperatures lower than 300°C were not significantly influenced by the covalent linkage of caffeic acid and genipin to chitosan. Due to their characteristics, mainly higher antioxidant activity and lower solubility, these are promising materials to be used as active films.
    Carbohydrate polymers. 01/2013; 91(1):236-43.
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    ABSTRACT: The study carried out in this work concerns the structural characterization of pectic polysaccharides from plum (Prunus domestica L.) and pear (Pyrus communis L.) cell walls and commercial pectic polysaccharides, obtained from Citrus. The α-(1 → 4)-d-galacturonic acid backbone was submitted to a selective hydrolysis with endo-polygalacturonase (EPG) and the fractions with low molecular weight (<1 kDa) obtained by size-exclusion chromatography were analysed by mass spectrometry using electrospray ionisation (ESI-MS). The ESI-MS spectra obtained revealed the presence of several [M+Na]+ ions of pectic oligosaccharides identified as belonging to different series, including oligosaccharides constituted only by galacturonic acid residues (GalAn, n = 1–5) and galacturonic acid residues substituted by pentose residues (GalA3Pentn, n = 1–2). Surprisingly, it was also observed the occurrence of galacturonic acid residues substituted by hexose residues (GalAnHexm, n = 2–4, m = 1–2). The fragmentation of the observed [M+Na]+ ions, obtained under ESI-MS/MS and MSn allowed to confirm the proposed structures constituent of these pectic oligosaccharides. Furthermore, the ESI-MSn spectra of the ions that could be identified as GalAnHexm (n = 2–4, m = 1–2) confirmed the presence of Hex or Hex2 residues linked to a GalA residue. Methylation analysis showed the presence, in all EPG treated samples, of terminally linked arabinose, terminally and 4-linked xylose, and terminally and 4-linked glucose. The occurrence of GalA substituted by Glc, and Glc-β-(1 → 4)–Glc are structural features that, as far as we know, have never been reported to occur in pectic polysaccharides.
    Carbohydrate Polymers 01/2012; 87(1):620-626. · 3.92 Impact Factor
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    ABSTRACT: Sulfur dioxide (SO 2 ) is probably one of the most versatile and efficient additives used in winemaking due to its antiseptic and antioxidant properties. This compound is also important for minimizing phenolic polymerization rate and color loss during wine aging. However, allergies caused by SO 2 -derived compounds, namely the sulfites, are becoming more frequent, causing symptoms such as headaches, nausea, gastric irritation, and breathing difficulties in asthma patients. Consequently, the legislated maximum concentration of SO 2 allowed in wines has been gradually reduced. For this reason, it is crucial in a competitive global winemaking market strategy, to reduce or even eliminate the use of SO 2 as a preservative and to search for new healthier and safe strategies. This work gives an overview of the main methodologies that have been proposed so far and that have potential to be used in winemaking as an alternative to SO 2 . The addition of compounds such as dimethyl dicarbonate, bacteriocins, phenolic compounds, and lysozyme, and the use of physical methods, namely pulsed electric fields, ultrasound, ultraviolet radiation, and high pressure are discussed and critically evaluated.
    European Food Research and Technology 01/2012; 234(1):1-12. · 1.39 Impact Factor
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    ABSTRACT: Hydrophobized polysaccharides have emerged as a promising strategy in the biomedical field due to the versatility to design functional structures through the spontaneous self-assembly in cell-friendly conditions. Based on this concept, xanthan, a bacterial extracellularpolysaccharide with potential as encapsulating matrix, was conjugated with hydrophobic palmitoyl groups to obtain an amphiphilic system able to form capsules by self-assembly processes. The conjugation of xanthan was performed at different xanthan/palmitoyl chloride ratios and Fourier transformed infrared, 1H nuclear magnetic resonance spectroscopies, as well as wide angle X-ray diffraction, differential scanning calorimetry were performed to characterize the obtained conjugates. The results showed that the increase in the hydrophobic reactant promoted higher hydrophobic interaction and consequently higher molecular organization. At certain palmitoyl concentrations and through a proper balance between charge repulsion and hydrophobic interaction, the amphiphilic molecules self-assembled into stable capsular hollow structures in the presence of physiological ion concentration and pH. Poly-L-lysine coated microcapsules with an average diameter of 576.6 ± 74 μm and homogenous size distribution were obtained. The morphology revealed by scanning electron microscopy showed microcapsules with two distinct layers. The ability of palmitoyl-xanthan microcapsules to sustain viability and proliferation of encapsulated cells was confirmed by AlamarBlue and DNA assays. These findings suggest the application of palmitoyl-xanthan microcapsules as a potential material for cell encapsulation in cell-based therapies.
    Soft Matter 10/2011; 7(20):9647-9658. · 4.15 Impact Factor
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    ABSTRACT: The sun-dried pear of S. Bartolomeu (Pyrus communis L. var. S. Bartolomeu) is a traditional sweet food product of unique elastic properties and reddish brown colour. Alternative drying methodologies to replace the traditional open air sun-drying procedure are under development, namely the use of greenhouses with and without air convection and a hot air tunnel. To test whether the Maillard reactions can contribute to the colour of this traditional product, the profiles of free and bound amino acids constituents of the pulp of fresh pears as well as pears processed according to different drying methodologies were evaluated. Also, the occurrence of furosine, carboxymethyllysine (CML) and carboxyethyllysine (CEL), indicative of Maillard reaction, was diagnosed and quantified. The drying of the pears affects the free amino acid profile, increasing proline content and decreasing aspartic and glutamic acids. Although the proteic amino acid profile was not significantly modified with the drying process, a loss of the relative content of Lys was observed. This loss was related with the increase in the amount of furosine, CML and CEL formed during the drying of the fruits. Although all drying methods tested promoted the increase in the amount of CML, CEL and furosine, this increase was higher in the case of the traditional sun-drying and greenhouse processing, where the fruits presented reddish brown colour, and lower for the hot air tunnel processing, where the fruits became less intense. These results allow affirming that the drying process promotes the occurrence of Maillard reaction, contributing to the characteristic reddish brown colour of the final product.
    European Food Research and Technology 10/2011; · 1.39 Impact Factor
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    2nd International Conference Wine Active Compounds, Beaune, France; 03/2011
  • Olives and Olive Oil in Health and Disease Prevention, Edited by Victor R. Preedy and Ronald Ross Watson, 07/2010: pages 325-332; Oxford: Academic Press., ISBN: 978-0-12-374420-3

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