https://repositorio.ufpb.br/jspui/handle/123456789/2405 2026-04-08T22:27:15Z https://repositorio.ufpb.br/jspui/handle/123456789/37893 Título: Secagem em camada de espuma de folhas de kalanchoe laetivirens: testes preliminares para definição de parâmetros Autor(es): Muniz, Larissa Oliveira Orientador: Cavalcante, Josilene de Assis Abstract: Kalanchoe laetivirens, popularly known as aranto, has attracted scientific interest due to the presence of bioactive compounds associated with various pharmacological activities. However, the high moisture content of its leaves hinders preservation, making it necessary to apply processing techniques that enhance stability and facilitate its use. In this context, foam-mat drying stands out as an efficient alternative for dehydrating liquid or pasty plant materials, as it increases the contact surface area with the drying air, thereby reducing processing time. Thus, the aim of this study was to evaluate the feasibility of foam-mat drying of Kalanchoe laetivirens leaves, focusing on defining suitable parameters for foam formation and analyzing the influence of temperature on the drying process. Initially, experiments were carried out to characterize the foam by evaluating parameters such as density, expansion (overrun), and stability, using the foaming agent Emustab under different experimental conditions (variations in juice dilution, emulsifier concentration, and whipping time). Based on the results, experiment 7 was identified as the most suitable condition, corresponding to lower juice dilution, higher emulsifier concentration, and longer whipping time, which resulted in lower density, higher air incorporation, and greater foam stability. Subsequently, the foam obtained under the selected conditions was subjected to drying at different temperatures (50 °C, 60 °C, and 70 °C) in order to evaluate the influence of this variable on the material behavior during the process. The results indicated that 60 °C presented the best performance among the evaluated conditions, providing lower water activity, higher titratable acidity, and absence of significant structural changes, such as cracks in the dried layer, in addition to reduced indications of thermal degradation. Therefore, foam-mat drying proved to be a promising technique for dehydrating Kalanchoe laetivirens leaves, contributing to the production of a more stable powder with potential for future applications. Editor: Universidade Federal da Paraíba Tipo: TCC 2026-03-20T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/37892 Título: Análise funcional da bactéria tb3 isolada da rizosfera do tamboril (Enterolobium contortisiliquum) e avaliação do potencial como bioinsumo agrícola Autor(es): Galvão, Izabella Lins Orientador: Santos, Sharline Florentino de Melo Abstract: Rhizobacteria are microorganisms that colonize the rhizosphere and provide beneficial effects to plants through different mechanisms, such as phytohormone synthesis, mineral solubilization, nitrogen fixation, and enhanced nutrient uptake. The use of microbial inoculants has gained prominence in recent decades for strengthening the biological component of production systems, reducing dependence on synthetic fertilizers, and contributing to agricultural sustainability. In this context, the present study aimed to confirm whether a bacterium isolated from the rhizosphere of Tamboril exhibits characteristics of a plant growth–promoting microorganism, as well as to evaluate its growth in a commercial medium and in alternative media formulated from watermelon products and by-products. The TB3 bacterium was characterized regarding its capacity for phosphate solubilization, biological nitrogen fixation, and production of indole-3-acetic acid (IAA). Subsequently, microbial growth kinetics were evaluated in nutrient broth and in an alternative medium based on watermelon juice, as well as the influence of pH, total reducing sugar concentration, and temperature on cell growth and IAA production. Cultivations were also performed with different concentrations of watermelon juice and in media formulated from the liquid and solid fractions of the fruit peel. The results indicated that TB3 presents functional characteristics compatible with plant growth–promoting microorganisms, in addition to satisfactory growth in alternative media formulated with watermelon juice and peel. The use of watermelon residue proved to be viable for bacterial cultivation, demonstrating potential for cost reduction and reuse of agro-industrial residues. Bioinoculant assays showed positive effects on the initial development of plants, especially when the application occurred after germination. Therefore, this study highlights the potential of the TB3 bacterium for use as an agricultural bioinoculant associated with sustainable strategies for the valorization of plant residues. Editor: Universidade Federal da Paraíba Tipo: TCC 2026-03-09T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/37649 Título: Síntese de novos derivados híbridos de 1,2,4-oxadiazol contendo núcleos de cumarina e piridina Autor(es): Silva, Gildilayne Medeiros da Orientador: Vale, Juliana Alves Abstract: The synthesis of hybrid compounds has attracted considerable interest in Organic and Medicinal Chemistry, since the combination of different bioactive scaffolds within a single molecular framework may lead to molecules with enhanced pharmacological properties and increased structural diversity. In this context, the incorporation of the 1,2,4-oxadiazole core into widely studied heterocyclic systems, such as coumarins, represents a promising approach, considering the well-documented biological activities associated with both classes of compounds. Accordingly, the present work focused on the investigation and application of an efficient synthetic methodology for the preparation of novel coumarin–1,2,4-oxadiazole–pyridine hybrid derivatives through a one-pot coupling between coumarin-3-carboxylic acid and pyridinyl amidoximes. The first step involved the synthesis of coumarin-3-carboxylic acid (1) via a Knoevenagel condensation, employing chitosan as a recyclable catalyst in an aqueous medium, affording an isolated yield of 82% within a short reaction time (10 min). In parallel, three pyridinyl amidoxime isomers (2a–c) were synthesized from hydroxylamine hydrochloride and the corresponding cyanopyridines, using water and ethanol as solvents at room temperature, with satisfactory reaction times (30–120 min) and high yields (82–92%). In the subsequent step, the coupling between the precursors was carried out using different activation systems for coumarin-3-carboxylic acid, namely EDCI/HOBt and DCC in DMF under reflux conditions. Among the conditions evaluated, the EDCI/HOBt system proved to be the most efficient for the formation of the 1,2,4-oxadiazole hybrid derivatives, furnishing products 3a and 3b in moderate yields (60–65%) after six hours of reaction. The obtained compounds were characterized by 1H and 13C Nuclear Magnetic Resonance spectroscopy, confirming the formation of the 1,2,4-oxadiazole core and the structural consistency with the proposed molecular structures. Editor: Universidade Federal da Paraíba Tipo: TCC 2026-02-11T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/36351 Título: Avaliação das propriedades mecânicas e superficiais de bioplásticos à base de amido e reforçados com bagaço de cana-de-açúcar e sisal Autor(es): Siqueira, Denner Cunha Orientador: Soares Filho, José Elson Abstract: This work aims to study the production of bioplastic from sugarcane bagasse and sisal fibers. These raw materials are abundant in Brazil, and in Paraíba alone, millions of tons of bagasse are produced per harvest. Due to the environmental problems that conventional plastics pose to the environment, this work will attempt to improve the production method of a bioplastic using sugarcane bagasse and sisal fibers using a methodology previously chosen for the experiments. This methodology addresses the importance of alkaline treatment of the fibers to improve their performance—that is, a bioplastic with properties similar to those of petrochemical-based plastics. A bioplastic must have the advantage of being biodegradable, unlike conventional plastics, as well as good mechanical properties, for example. In addition to the alkaline treatment, potato starch was used as the agent to form the bioplastic film, as it is a starch-rich reagent and a glucose supplier for the reaction. The developed films were analyzed using tensile and profilometry tests, demonstrating their strength and roughness. Furthermore, their visual properties, such as color and fiber arrangement, were evaluated. The tensile strength and roughness results were compared with the literature and showed promising results, especially for sisal fibers. Editor: Universidade Federal da Paraíba Tipo: TCC 2025-10-13T00:00:00Z