Percorrer por autor "Vega-Baudrit, Jose Roberto"
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- 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.
- Synthesis of chitosan nanoparticles (CSNP): effect of CH-CH-TPP ratio on size and stability of NPsPublication . Des Bouillons-Gamboa, Rosvin E.; Oca-Vásquez, Gabriela Montes de; Vega-Baudrit, Jose Roberto; Ríos Duarte, Liz Carolina; Lopretti, Mary; Rentería Urquiza, Maite; Zúñiga-Umaña, Juan Miguel; Barreiro, M.F.; Vázquez, PatriciaIn the face of a pressing global issue-the escalating threat of antibiotic resistancethe development of new antimicrobial agents is urgent. Nanotechnology, with its innovative approach, emerges as a promising solution to enhance the efficacy of these agents and combat the challenge of microbial resistance. Chitosan nanoparticles (CSNPs) stand out in biomedical applications, particularly in the controlled release of antibiotics, with their unique properties such as biocompatibility, stability, biodegradability, non-toxicity, and simple synthesis processes suitable for sensitive molecules. This study synthesized CSNPs using the ionotropic gelation method, with tripolyphosphate (TPP) as the crosslinking agent. Various CS: TPP ratios (6:1, 5:1, 4:1, 3:1, 2:1) were tested, and the resulting nanoparticles were evaluated using dynamic light scattering (DLS). The CS: TPP ratio of 4:1, with an average hydrodynamic diameter (DHP) of (195 ± 10) nm and a zeta potential of (51 ± 1) mV, was identified as the most suitable for further analysis. The characterization of NPs by Transmission Electron Microscope (TEM) and atomic force microscopy (AFM) revealed diameters of (65 ± 14) nm and (102 ± 18) nm, respectively. Notably, CSNPs exhibited significant aggregation during centrifugation and lyophilization, leading to diameter increases of up to 285% as measured by AFM. The antibacterial activity of CSNPs against Staphylococcus aureus and Escherichia coli was assessed using the resazurin assay. It was found that CSNPs not subjected to centrifugation, freezing, and lyophilization retained their antimicrobial activity. In contrast, those that underwent these processes lost their efficacy, likely due to aggregation and destabilization of the system. This study presents a straightforward and effective protocol for encapsulating sensitive active agents and synthesizing chitosan nanoparticles, a potential system with significant implications in the fight against antibiotic resistance.