https://tede.unioeste.br/handle/tede/586 2026-09-19T16:59:27Z https://tede.unioeste.br/handle/tede/8658 Title: Elaboração de produtos à base de tilápia do Nilo (Oreochromis niloticus) para alimentação humana Autor: Dentz, Bruna Alessandra Von Primeiro orientador: Feiden, Aldi Abstract: As global fish production increases, new fish-based products are being developed and marketed to introduce and encourage consumption among those who do not typically eat fish. This study aimed to analyze two products: the first involved the production of jarred tilapia presented both as whole fillets and as a pâté which underwent sensory, shelf-life, and microbiological analyses. Results showed that while the whole-fillet product was well-accepted by consumers, the pâté version performed even better; this demonstrates that producing such items offers a sustainable way to utilize fish that would otherwise be discarded by the industry for failing to meet commercial standards. The second product was a pizza dough made from rice and oat flours with and without added fish flour designed for individuals with wheat, milk, or egg intolerances or allergies. It specifically targets consumers who enjoy fish but seek options that accommodate their dietary restrictions while offering convenience through unconventional formats, such as enriched doughs. Affective sensory analyses specifically acceptance and purchase intention tests were conducted; both products received similar scores and were well-received by panelists. The study concludes that these products add value to fish in a straightforward manner, making the manufacture of items like pizza dough an excellent option for micro-enterprises or small-scale agro-industries. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Tese 2026-04-24T00:00:00Z https://tede.unioeste.br/handle/tede/8655 Title: Filme polimérico fotocatalítico a base de polímero biodegradável com TiO2 para degradação do corante vermelho BF-4B Autor: Rosenberger, Andressa Giombelli Primeiro orientador: Modenes, Aparecido Nivaldo Abstract: Due to environmental pollution from textile industries, there has been interest in removing dyes from processes such as dyeing and washing. In this context, the application of polymeric fibers electrospun with TiO2 in the photodegradation of the dye Red BF-4B was studied. To produce the polymeric yarns, the polymer blend PBAT/PLA and TiO2 nanoparticles were used. The polymer solution was formed by dissolving the polymer (15% m/v) in a solvent mixture of chloroform and dimethylformamide (85:15% v/v) and finally adding the TiO2 nanoparticles (10% m/v) ). The fibers were electrospinned using the conditions of flow of 1.80 mL h-1, distance of 16 cm and voltage of 18 kV. The fibers obtained were characterized by morphological, structural and thermal techniques, then the photocatalytic tests were carried out and, finally, the viability of the polymeric film was evaluated after the photocatalytic process. PBAT/PLA/TiO2 fibers have cylindrical morphology with an average diameter of 1.12±0.26 μm, in addition they are rough and have small bumps along their lengths due to the presence of TiO2. By TEM analysis, it is possible to verify the dispersion of TiO2 nanoparticles along the fibers, and it is noted that the polymer surrounds them by a thin layer. Both fibers with and without TiO2 have a hydrophobic character at the beginning of the contact angle wettability analysis, but after 75 min the wettability increases due to physical mechanisms such as wetting and encrustation. The FTIR spectra show characteristic functional groups of PBAT and PLA polymers and in the fibers with TiO2 nanoparticles it is observed in the region between 1000 and 650 cm-1 Ti-O-Ti oscillations dominant over the characteristic bands of the polymer. In PBAT/PLA and PBAT/PLA/TiO2 fibers, the presence of an amorphous halo characteristic of PBAT/PLA polymer blends can be seen in X-ray diffractograms. Thermal analysis indicates a conformational change, so that the PLA polymer demonstrates greater stability, as opposed to the PBAT polymer, which became easier to be degraded. The pHpcz of the materials indicates that for anionic dyes such as BF-4B Red, a pH below 7.42 would facilitate the catalytic process. Furthermore, the mathematical adjustments indicate that at the beginning of the reaction, the kinetic model that best fits the experimental data is the zero-order model, then, at lower concentrations, the model becomes the pseudo-first-order model. The reuse of polymeric film showed good removals (86.60 to 93.07%) during six cycles of 600 min. After the photocatalytic process, in the first and sixth degradation cycle, the fibers remain cylindrical, with prominent protrusions, the presence of several fractured fibers and a reduction in their diameters, indicating degradation and wear of the polymer. Infrared vibrational spectra show that most of the functional groups did not change, except for the regions at 1755 (C=O) and 1714 cm-1 (C-O), showing a possible conformational alteration of the polymeric chains. The thermal degradation profiles also changed, but the maximum thermal decomposition temperatures showed few changes after the photocatalysis process and the thermal degradation began to increase slightly after the cycles. Furthermore, by X-ray diffractograms it is observed that TiO2 particles are more exposed after photocatalysis, demonstrating loss of polymeric material during this process. Thus, it is emphasized that PBAT/PLA fibers produced by the electrospinning technique are promising to be used as support material for the photocatalyst (TiO2) and application in the treatment of textile dye residues. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Tese 2021-12-20T00:00:00Z https://tede.unioeste.br/handle/tede/8651 Title: Análise de operabilidade da produção de gás de síntese a partir do processo sequencial de reforma a seco e reforma a vapor do biogás Autor: Costa Sobrinho, Thales Uchoa da Primeiro orientador: Borba, Carlos Eduardo Abstract: This dissertation presents a mathematical modeling-based integrated analysis of synthesis gas (syngas) production from biogas through the sequential combination of dry reforming of methane (DRM) and steam reforming of methane (SRM) processes. The adopted methodology involved the development of a thermodynamic model based on the minimization of Gibbs free energy, accounting for non-idealities via the fugacity coefficient of each species in the mixture, capable of predicting the equilibrium composition of the involved species, and its validation using experimental data from the literature. The study assessed the impact of operational variables such as temperature (in the range of 600–1500 K), CH4/CO2 feed molar ratio (1.5 to 4), and water vapor molar flow rate (4 to 16 kmol·h−1) on process outputs such as syngas composition, H2/CO molar ratio, and carbon formation. The best results were obtained at temperatures of 1000 K and 1150 K in the DRM (R1) and SRM (R2) reactors, respectively, CH4/CO2 feed ratio ≥ 1.5, and a steam flow rate of 8 kmol·h−1, corresponding to a steam-to-carbon ratio (S/C) of 1.33. These conditions enabled the achievement of an H2/CO ratio ≥ 2.0, high reactant conversion, and low carbon formation, under operating conditions comparable to those used in industrial reformers. Furthermore, the operability index (OI) was determined as an optimization tool, identifying safe and efficient operational regions of the process. The OI reached a value of 81.64%, indicating a good overlap between achievable and desirable output sets. The results demonstrate that the reforming process employing sequential reactors is a viable and promising alternative for the conversion of the main components of biogas into synthesis gas, offering high flexibility and selectivity - especially when combined with operability analysis methods - thus contributing to the development of sustainable syngas production technologies from renewable waste sources. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Dissertação 2025-07-17T00:00:00Z https://tede.unioeste.br/handle/tede/8647 Title: Fotossensibilizadores naturais e sintéticos aplicados à inativação fotodinâmica antimicrobiana: caracterização fotoquímica, espectroscópica e avaliação biológica Autor: Marcon, Caroline Toigo Primeiro orientador: Fiorese, Monica Lady Abstract: Antimicrobial resistance and foodborne and cutaneous infections have intensified the search for alternative antimicrobial strategies. Antimicrobial photodynamic inactivation (aPDI) has emerged as a promising approach based on the generation of reactive oxygen species through the interaction of a photosensitizer, light, and molecular oxygen, exerting multifactorial effects on microbial cellular structures. This study investigated the potential of natural and synthetic photosensitizers for antimicrobial aPDI through phytochemical, spectroscopic, and photochemical characterization, assessment of antioxidant activity, and determination of antimicrobial efficacy against microorganisms of clinical and food-related relevance. In addition, a standardized aPDI protocol was developed and integrated into a custom-built LED illumination system designed for 96-well microplates. The system enabled irradiance control, wavelength selection, and homogeneous light distribution, allowing the simultaneous assessment of photosensitizer concentration and optical fluence with improved reproducibility and experimental throughput. The phenothiazinium dyes Azure A (AZA) and Toluidine Blue O (TBO) were evaluated as synthetic photosensitizers, whereas a hydroethanolic extract obtained from the flowers of Plumeria rubra L. (Apocynaceae) by ultrasound-assisted extraction was investigated as a natural photosensitizer. AZA and TBO exhibited absorption profiles in the visible region that were compatible with the red LED source used at 630 nm. Both dyes showed similar singlet oxygen generation rates and photodynamic saturation at concentrations above 34 µM. In the aPDI assays, both photosensitizers achieved complete inactivation of Cutibacterium acnes at the same concentrations, with minimum bactericidal concentrations (MBCs) ranging from 6.25 µM at 12 J/cm² to 0.78 µM at 50 J/cm². Against Staphylococcus epidermidis, AZA exhibited greater efficacy than TBO, with MBC values twofold lower at all evaluated fluences. Phytochemical analysis of the Plumeria rubra extract by UHPLC–MS/MS identified 21 compounds, with rutin (83.96 mg/g) and chlorogenic acid (13.38 mg/g) as the predominant constituents. The extract exhibited high antioxidant activity in the TBARS assay (EC₅₀ = 0.145 mg/mL) and broad spectral absorption between 400 and 630 nm, which was compatible with the white-light source used. In the absence of light, the extract showed no antibacterial activity under the tested conditions. Upon irradiation, however, it induced fluence-dependent photodynamic inactivation of all six Gram-positive strains evaluated, including methicillin-resistant Staphylococcus aureus (MRSA), with an MBC of 0.78 mg/mL at 18 J/cm². Lower efficacy was observed against Gram-negative bacteria.These findings demonstrate that AZA is an effective synthetic photosensitizer for antimicrobial photodynamic inactivation, with potential applications in the treatment of acne vulgaris. Furthermore, the Plumeria rubra extract represents a promising natural photosensitizer, combining a relevant phytochemical profile, photodynamic selectivity, and bactericidal activity against pathogens of clinical and food-related importance, including multidrug-resistant strains. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Tese 2026-07-27T00:00:00Z