Percorrer por autor "Santamaria-Echart, Arantzazu"
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- Advances in waterborne polyurethane and polyurethane-urea dispersions and their eco-friendly derivatives: a reviewPublication . Santamaria-Echart, Arantzazu; Fernandes, Isabel P.; Barreiro, M.F.; Corcuera, Maria Angeles; Eceiza, ArantaxaPolyurethanes and polyurethane-ureas, particularly their water-based dispersions, have gained relevance as an extremely versatile area based on environmentally friendly approaches. The evolution of their synthesis methods, and the nature of the reactants (or compounds involved in the process) towards increasingly sustainable pathways, has positioned these dispersions as a relevant and essential product for diverse application frameworks. Therefore, in this work, it is intended to show the progress in the field of polyurethane and polyurethane-urea dispersions over decades, since their initial synthesis approaches. Thus, the review covers from the basic concepts of polyure-thane chemistry to the evolution of the dispersion’s preparation strategies. Moreover, an analysis of the recent trends of using renewable reactants and enhanced green strategies, including the current legislation, directed to limit the toxicity and potentiate the sustainability of dispersions, is described. The review also highlights the strengths of the dispersions added with diverse renewable additives, namely, cellulose, starch or chitosan, providing some noteworthy results. Similarly, dispersion’s potential to be processed by diverse methods is shown, evidencing, with different examples, their suitability in a variety of scenarios, outstanding their versatility even for high requirement applications.
- Advancing Pickering emulsions with natural-based solid dispersion particles: Particle screening and design of pectin-based emulsionsPublication . Rezende, Stephany; Santamaria-Echart, Arantzazu; Ribeiro, Andreia; Dias, Madalena M.; Barreiro, FilomenaGiven the evolving trends in consumption, Pickering emulsions are emerging as a promising solution for functional and healthier foods, highlighting the need to diversify particle stabilisers. This study assessed the potential of curcumin-based solid dispersions (SDs) prepared with natural polymers (pectin, maltodextrin, Arabic gum, potato starch, and k-carrageenan) as Pickering stabilisers. Among these, pectin-curcumin SDs (contact angle = 48.0 ± 3.6◦) demonstrated effective emulsion stabilisation, as confirmed by confocal microscopy. The impact of oil volume fraction (φ = 0.20–0.70) and SD concentration (1.0–5.0 % wt.) on emulsion stability was evaluated. An intermediate φ (0.45) consistently minimised creaming index (CI = 0–16.67 %) and droplet size (D[4,3] =2.53–4.12 μm). Complete reduction of creaming (CI = 0 %) was achieved at high SD concentration with low φ or low SD concentration with high φ, leading to improved stability. The three produced optimised formulations exhibited distinct colour properties (L* = 64.06–72.00, a* = 11.09–12.50, b* = 55.10–60.70), with hues ranging from yellow to orange, highlighting their potential for natural colouring applications. Rheological behaviour varied from gel-like (G’ > G”) to viscoelastic (G’ = G”), broadening their potential in food formulations. Higher SD concentrations with lower/intermediate φ produced structured, gel-like emulsions suitable for sauces or spreads. In contrast, lower SD concentrations with higher φ yielded fluid emulsions for dressings or beverages. These findings highlight the feasibility of SD-based Pickering emulsions for designing stable (≥30 days), visually appealing, and texturally versatile food products.
- Bacteriostatic ecffect of waterborne polyurethane-ureia films containing bioactive plant extracts incorporated by different routesPublication . Santamaria-Echart, Arantzazu; Fernandes, Isabel P.; Arbelaiz, Aitor; Barreiro, M.F.; Corcuera, Maria Angeles; Eceiza, ArantaxaThe environmental awarenessh as promoted the development of new materiats towards eco-friendty systems based on both,green synthesis processes as well as the renewable origin of the raw compounds. In this way,focusing on synthesis methods, the use of waterborne polyurethane-urea dispersions have gained attention due to their versatility leading to a wide variety of apptications broadening the range of appLications. In addition, it is worth nothing that the dispersibitity in water offers the possibitity of incorporating soluble additives such as plant extracts. Therefore, in this work Melissa officinalis L . ptant was setected in order to obtain bioactive plant extract, in order to be incorporated to a waterborne polyurethane-urea disspersion varying their content as well as using three differernt incorporation routes. These dispersions were characterized and employed in the preparation of films which were analyzed from the viewpoint of physicochemical, thermal and mechanical properties, among others. Finatty, the antibacterial properties of the films were analyzed after 1 and 4 days of incubation. Where it was observed that the content and incorporation route of the extract influenced in the behavior of the films against common pathogens (Staphylococcus aureus, Escherichio coli ond Pseudomonas aeruginosa.
- Bioinks functionalized with natural extracts for 3D printingPublication . Larraza, Izaskun; Santamaria-Echart, Arantzazu; Fernandes, Isabel Rodrigues; Barreiro, M.F.; Arbelaiz, Aitor; Eceiza, ArantaxaIn the search of materials valid for direct ink writing (DIW) 3D printing and with special interest for the biomedical and pharmaceutical applications, the development of bioactive inks for DIW is of great interest. For that purpose, in this work bioactive waterborne polyurethane–urea inks were prepared by addition of natural extracts (logwood, chestnut, and alder buckthorn) and cellulose nanofibers (CNF). The rheological behavior of the inks proved to be strongly dependent on the extract type and content, and the addition route used. Inks prepared by ex-situ incorporation of the extracts showed a strong gel-like behavior, as did inks prepared with chestnut and alder buckthorn extracts, which, in turn, hindered a continuous flow during the printing process, resulting in 3D printed parts with poor shape fidelity. On the other hand, inks prepared insitu and with logwood extract showed more facility to flow and higher homogeneity, which translated in better printability and better shape fidelity, further enhanced for CNF containing inks. 3D printed composites showed reinforced mechanical behavior, as well as in materials with enhanced antibacterial behavior. Overall, the possibility to successfully prepare bioactive inks valid for 3D printing was proven.
- Biorefinery of Lignocellulosic and Marine Resources for Obtaining Active PVA/Chitosan/Phenol Films for Application in Intelligent Food PackagingPublication . Lopretti, Mary; Batista-Menezes, Diego; Rezende, Stephany; Santamaria-Echart, Arantzazu; Barreiro, M.F.; Vega-Baudrit, Jose RobertoThis study focuses on the extraction of phenolic compounds from the fermentation of Phanerochaete chrysosporium and Gloeophyllum trabeum. The main goal was to synthesize phenol/chitosan microspheres and PVA films and characterized using FTIR, TGA, DSC, SEM, and mechanical tests to evaluate their physical, chemical, and mechanical properties for antimicrobial packaging applications. Homogeneous chitosan microspheres loaded with lignin-derived phenols were obtained, showing controlled release of antimicrobial compounds. The incorporation of phenolic microspheres into PVA/chitosan films resulted in significant improvements in mechanical properties: the films exhibited an elastic modulus of 36.14 ± 3.73 MPa, tensile strength of 12.01 ± 1.14 MPa, and elongation at break of 65.19 ± 5.96%. Thermal tests revealed that chitosan-containing films had enhanced thermal stability, with decomposition temperatures (T10) reaching 116.77 ◦C, compared to 89.28 ◦C for pure PVA. In terms of antimicrobial activity, PVA/chitosan/phenol films effectively reduced Lactobacillus growth and milk acidity, maintaining quality for up to 96 h at room temperature, outperforming controls with acetic acid and H2O2. The films also inhibit yeast growth for one week. In conclusion, phenols can be effective antimicrobial agents in dairy, but their use should be monitored. Additionally, PVA/chitosan-phenol films offer biodegradability, antimicrobial properties, and sustainability for diverse applications.
- Biosynthesis of antioxidant xanthan gum by Xanthomonas campestris using substrates added with moist olive pomacePublication . Crugeira, Pedro Jorge Louro; Almeida, Heloísa H.S.; Marcet, Ismael; Rendueles, Manuel; Pires, Marcella Golini; Rafael, Helder Martins; Rodrigues, Ana Isabel G.; Santamaria-Echart, Arantzazu; Rafael, Helder; Barreiro, M.F.; Pires, Marcella GoliniMoist olive pomace (MOP) is a high moisture content by-product of the olive oil industry. Managing this recalcitrant residue (transport, storage, and drying) is a priority demanding investment in finding alternative valorisation routes. In this context, the biosynthesis of xanthan gum (XG) incorporating MOP in the substrate (0.0 %, 5.0 %, 10.0 %, 15.0 %, 20.0 %, 25.0 %, 30.0 % and 50.0 %) to induce bacterial stress was attempted. XG biosynthesis yield was quantified, and the product was characterised by structural analysis (FTIR), thermal behaviour (TG), rheology and antioxidant capacity. Relative to the control (sample with no added MOP), a significant increase in XG biosynthesis was found for concentrations up to 30.0 % MOP. In particular, for XG produced with 15 % MOP, a 50.91 % (p < 0.0001) increase was achieved, together with 395.78 % for viscosity. In general, XG produced with MOP presence showed antioxidant activity, a value-added property, especially for applications in the food, pharmaceutical and cosmetic areas. The results indicated that the stress imposed by the MOP induced a microbial response leading to XG production increase, structural and viscosity modifications, and antioxidant properties incorporation. Overall, this work points out a new MOP application contributing to the sustainability of the olive oil productive chain from a biobased circular economy perspective.
- Chitosan-xanthan gum-based hydrogels loaded with essential oil distillation by-products of Aloysia citrodora Paláu for antimicrobial systemsPublication . Almeida, Heloísa H.S.; Santamaria-Echart, Arantzazu; Amaral, Joana S.; Aquino, Leandro Lima ; Rodrigues, Alírio E.; Barreiro, FilomenaHydrogels, 3D hydrophilic networks formed by oppositely charged biopolymers like chitosan and xanthan gum, offer a safe, non-toxic, and biocompatible option for delivery applications. Essential oil (EO) by-products, such as hydrosols and wastewater, are sources of antioxidant and antimicrobial compounds, but their high dilution can limit direct applications. In this context, this work focused on the development of hydrogels via electrostatic complexation incorporating hydrosol and wastewater by-products from the steam distillation of Aloysia citrodora Palau, using a two-stage approach: (a) initial loading during hydrogel formation and (b) subsequent reloading of the hydrogels to further enhance the concentration of bioactive compounds. The effect of pH (4, 7, and 11) on polymer complexation was evaluated, as it influences polymer-polymer and polymer-bioactive compound interactions by modifying the protonation and deprotonation states of their functional groups. This effect was evident in swelling, release kinetics, morphology, and rheological properties. Fourier-transform infrared (FTIR) analysis confirmed the successful formation of the polymer complex. Neutral pH hydrogels showed the highest hydrosol entrapment (70.3%) and were selected as the most promising systems. Biological characterisation showed that the reloading process enhanced bioactivity. Wastewater-load-reload improved antioxidant capacity, driven by the high phenolic content. Moreover, hydrosol-loaded-reload systems exhibited antimicrobial activity, with bactericidal effects against Staphylococcus aureus and Escherichia coli, outperforming both unloaded and loaded systems. These findings highlight the potential of loading and reloading steps to valorise EO by-products, producing sustainable, functional hydrogels with high bioactivity, suitable for food, pharmaceutical, medical, and biotechnological applications.
- Developing High-Coloring Natural Systems Using Double Emulsions with Daucus carota L. Extract to Meet High-Performance RequirementsPublication . Teixeira, Liandra Gracher; Silva, Samara Cristina; Colucci, Giovana; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Barreiro, M.F.Daucus carota L. extract is attracting interest as a natural colorant alternative. However, the presence of anthocyanins (ACNs), which are sensitive to pH changes, limits its application. To tackle this issue, water-in-oil-in-water (W1/O/W2) double emulsions are emerging as innovative solutions. Nevertheless, the problem of reaching robust colorant systems for industrial use still needs to be overcome. One important target is to reach a high coloring power, minimizing its impact on the final product. In this context, the effect of colorant concentration and the volume of the primary emulsion, two routes to increase the colorant power, on color attributes and stability, an important feature to reach a marketable product, was studied. The optimal experimental design was conducted to two optimal solutions, whether through heightened colorant concentration or primary emulsion volume: a 41/59 (W1/O)/W2 ratio with 11 wt.% colorant, and a 48/52 (W1/O)/W2 ratio with 6 wt.% colorant, respectively. A subsequent assessment of color and physical emulsion stability over 30 days pointed out the solution with the lower colorant concentration (6 wt.%) as the one with better performance (L*: 44.11 ± 0.03, a*: 25.79 ± 0.01, D4;3: 9.62 ± 0.1 μm, and CI: 14.55 ± 0.99%), also minimizing the permeability of the colorant to the outer aqueous phase. Overall, these optimized emulsions offer versatile coloring solutions suitable for various industrial applications, such as food matrices and functional cosmetics.
- Development of chitosan microspheres through a green dual crosslinking strategy based on tripolyphosphate and vanillinPublication . Correa, Rodolpho Fagundes; Colucci, Giovana; Halla, Noureddine; Pinto, João A.; Santamaria-Echart, Arantzazu; Blanco, Silvia Priscila; Fernandes, Isabel P.; Barreiro, M.F.Microencapsulation procedures have recently focused attention on designing novel mi-crospheres via green synthesis strategies. The use of chitosan (CS) as an encapsulating material has increased interest due to its unique bioactive properties and the various crosslinking possibilities offered by their functional groups. The consolidation of the microspheres by physical crosslinking using sodium tripolyphosphate (TPP) combined with chemical crosslinking using vanillin (VA) open new opportunities in the framework of green dual crosslinking strategies. The developed strategy, a straightforward technique based on an aqueous medium avoiding complex separa-tion/washing steps, offers advantages over the processes based on VA, mostly using water-in-oil emulsion approaches. Thus, in this work, the combination of TPP crosslinking (3, 5, and 10 wt.%) via spray-coagulation technique with two VA crosslinking methods (in situ and post-treatment using 1 wt.% VA) were employed in the preparation of microspheres. The microspheres were characterized concerning morphology, particle size, physicochemical properties, thermal stability, and swelling behavior. Results revealed that the combination of 5 wt.% TPP with in situ VA crosslinking led to microspheres with promising properties, being an attractive alternative for natural bioactives encapsulation due to the green connotations associated with the process.
- Development of colloidal lignin particles through particle design strategies and screening of their Pickering stabilizing potentialPublication . Colucci, Giovana; Santamaria-Echart, Arantzazu; Silva, Samara Cristina; Teixeira, Liandra Gracher; Ribeiro, Andreia; Rodrigues, Alírio; Barreiro, M.F.Colloidal lignin particles (CLPs) have increased interest as green and sustainable materials for Pickering stabilizers, with particle design being an important step towards their effective use. In this context, the antisolvent precipitation method was selected to conduct a study aiming at understanding the effect of process variables (initial lignin concentration, antisolvent pH, final ethanol concentration, and antisolvent addition rate) on particle size, zeta potential, color parameters, and contact angle. Moreover, their Pickering stabilizing potential was preliminarily screened. The evaluation using a Fractional Factorial Design revealed that the particle size is significantly influenced by the initial lignin concentration (as it increases, larger particles are obtained) and the final ethanol concentration (as it increases, smaller sizes result). The zeta potential is significantly affected by the antisolvent pH and the initial lignin concentration; the increase in both parameters results in higher negative values. The color is significantly dependent on the used initial lignin concentration (as it increases, particles become lighter and the yellowish accentuates) and the antisolvent pH (as it increases, particles become darker). Both initial lignin concentration and final ethanol concentration increase promote hydrophobicity, whereas increasing the antisolvent pH and its addition rate turns particles more hydrophilic. Through this strategy, it was possible to achieve CLPs with promising Pickering stabilizing potential, putting in evidence the importance of understanding the production process to design effective particles for target applications.