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“Avaliação da eficiência do revestimento de quitosana no "tempo de prateleira" dos ovos de galinha”

2026-10-16T05:07:24Z

Título: “Avaliação da eficiência do revestimento de quitosana no "tempo de prateleira" dos ovos de galinha” Autor(es): Tolentino, Nayane Ortega Primeiro Orientador: Arruda, Eduardo Jose de Abstract: Chicken eggs are particularly important, being sources of protein with high nutritional value and economic relevance; however, their quality progressively deteriorates during storage due to the exchange of water vapor and carbon dioxide through the porosity of the shell. This research evaluated the performance of chitosan coating formulations in the preservation of eggs stored under non-refrigerated conditions. In the first phase, 168 eggs were distributed between Control (Q0%) and treatments with chitosan at Q0.5%, Q1.0%, and Q1.5% (w/v), prepared in 5% acetic acid and applied by complete immersion, followed by immediate removal after complete coating of the surface. For seven weeks, mass loss, density, Haugh Unit, Yolk Index, yolk proportion, colorimetry, shell strength, and yolk integrity were evaluated using general linear models and robust standard errors (HC3) when necessary. In the second stage, physicochemical and biological characterizations of the eggshell–coating interface were performed using FTIR-ATR, UV-Vis, fluorescence, SEM/EDS, point determination of water activity, and a challenge assay with Salmonella Typhimurium. The week and treatment × week interaction effects were observed (p < 0.001), but there was no overall treatment effect in the average week (p = 0.394); Q1.5% showed a nearly zero slope that was lower than that of the Control (p = 0.003). For the percentage density loss, the main analysis was restricted to weeks 1 to 4, prior to method saturation: the interaction was significant (p < 0.001), and the three coated treatments showed lower slopes than the Control (p < 0.001), with no difference demonstrated between concentrations. The sensitivity analysis for weeks 1 to 5 preserved the direction of the result (interaction: p = 0.031). The Haugh Unit (n = 73) and the Yolk Index (n = 71) decreased with storage (p < 0.001), with no overall treatment effect or significant interaction. The yolk proportion (n = 73) showed a week effect (p = 0.012) and a borderline treatment × week interaction (p = 0.0495), but none of the slopes of the coated treatments differed from that of the Control. In colorimetry, L* showed treatment and interaction effects (p = 0.041 and p = 0.030), while a* and b* were predominantly influenced by time, and shell strength showed no treatment effect or interaction. FTIR-ATR indicated a superficial contribution of functional groups compatible with chitosan, preserving the predominant calcium carbonate bands. SEM and EDS demonstrated localized morphological changes and nitrogen detection only in the coated samples, with EDS being interpreted as semi-quantitative. Optical analyses revealed comparative changes in reflectance, transmittance, absorption, and fluorescence. In the microbiological assay, Q1.5% showed a greater descriptive reduction in the recovery of Salmonella Typhimurium on the eggshell, but the absence of individual counts per replicate prevented inferential comparison between treatments. Taken together, the chitosan formulations modified the surface interface of the eggshell and showed potential as a barrier to water and gas exchange, with more consistent quantitative evidence for maintaining density and specific evidence of a lower mass-loss slope in Q1.5%, without demonstrating universal superiority of one concentration in the evaluated attributes. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação

Coberturas de solo como estratégia de manejo inicial para formação de sistemas agroflorestais no município de Glória de Dourados – MS

2026-10-16T05:07:26Z

Título: Coberturas de solo como estratégia de manejo inicial para formação de sistemas agroflorestais no município de Glória de Dourados – MS Autor(es): Militão , Fernanda Turini Primeiro Orientador: Pereira , Zefa Valdivina Abstract: Environmental patterns have been significantly modified as a result of climate change, intensified by high emissions of greenhouse gases from industrial processes, urban lifestyles, and inappropriate land use. Unlike natural climate variations, which occur slowly and allow ecosystems to adapt, changes resulting from anthropogenic activities have occurred rapidly and intensely, causing environmental impacts on a global scale, including in agriculture, forestry, and water resources. In tropical forests, deforestation for land use, especially for agricultural and livestock activities, constitutes one of the main factors driving climate change. In the state of Mato Grosso do Sul, the expansion of agriculture and monocultures has intensified deforestation, contributing to high carbon emissions and aggravating regional environmental challenges. This scenario imposes challenges for ecological restoration, requiring adaptive strategies that integrate climatic limits, ecological vulnerability, and the functionality of restored ecosystems, while reconciling production and conservation. In this context, agroforestry systems emerge as an efficient alternative for integrating environmental restoration and agricultural production. Based on species diversity and the principles of ecological succession, these systems optimize land use, contribute to carbon sequestration, increase soil organic matter, and strengthen resilience to climate change. Thus, this study evaluated the initial development of eleven plant species under different types of soil cover (Napier grass, gliricidia, and eucalyptus), compared with a control treatment, in an area undergoing conversion to an agroforestry system in the municipality of Glória de Dourados, Mato Grosso do Sul, Brazil. A total of 352 seedlings (88 seedlings of each species) were randomly distributed at a spacing of 5 × 5 m. The mulches were applied in a 1 × 1 m area around each seedling. Plant development was monitored quarterly for 12 months through measurements of height, stem diameter, and survival assessment. The data were subjected to statistical analyses (ANOVA or KruskalWallis test) and to the calculation of the relative growth rate (RGR). Mortality varied among treatments, with a significant difference observed only between the eucalyptus and Napier grass mulches. Survival ranged from 40.63% (coconut) to 96.88% (acerola and white ipê), with high mortality observed for coconut seedlings (59.38%). No significant differences were found for growth variables. The RGR was higher for stem diameter (0.78 mm·mm⁻¹·year⁻¹) than for height (0.32 cm·cm⁻¹·year⁻¹). It was concluded that mulching plays an important role in maintaining seedling survival, although no significant effect on growth was observed during the 12-month period. Considering the advancement of environmental degradation and the limitations of conventional production systems, this study is expected to contribute to the understanding of practices that favor seedling establishment. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação

Metais e metaloides em águas superficiais da Bacia do Rio Paraguai: distribuição espacial, ocorrência e lacunas de monitoramento ambiental

2026-10-02T05:07:17Z

Título: Metais e metaloides em águas superficiais da Bacia do Rio Paraguai: distribuição espacial, ocorrência e lacunas de monitoramento ambiental Autor(es): Papaya, Nicolau Uzum Primeiro Orientador: Barufatti, Alexeia Abstract: The Paraguay River Basin, covering approximately 1,095,000 km² across Brazil, Bolivia, Paraguay, and Argentina, contains one of the largest floodplain systems on the planet, supporting high biodiversity and economically important activities. Despite its environmental relevance, information on the occurrence of metals and metalloids in its surface waters remains spatially scattered, temporally discontinuous, and methodologically heterogeneous, hindering the development of an integrated transboundary assessment. This study aimed to compile, systematize, and critically analyze the scientific literature on the occurrence of these elements in the basin between 1995 and 2025. Following the application of inclusion and exclusion criteria, 19 peer-reviewed studies were selected, encompassing 41 water bodies and 158 sampling sites across the four countries. Concentrations were standardized to mg L⁻¹ and compared with limits established by Brazilian, Paraguayan, and Bolivian legislation. The spatial distribution of sampling sites was represented through georeferencing and spatial analysis using QGIS 3.34.4. Eleven elements were identified as recurrent in the basin: aluminum (Al), arsenic (As), cad mium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn). The highest concentrations were recorded in tributaries of the Bolivian portion of the basin, particularly in water bodies located above 2,000 m in altitude and associated with acid mine drainage in the Potosí region, where Fe reached up to 950 mg L⁻¹, Al 630 mg L⁻¹, and Zn 560 mg L⁻¹. The highest frequencies of limit exceedances were observed for Pb (n = 67), Cd (n = 49), and As (n = 47). Copper (Cu) showed different classifications depending on the legislation adopted. The spatial distribution revealed marked asymmetry among countries, with most studies concentrated in Brazil and Bolivia and limited sampling coverage in Paraguay and Argentina. These results demonstrate that metal and metalloid contamination in the Paraguay River Basin is recurrent and spatially heterogeneous, reinforcing the need for continuous, standardized, and cooperative monitoring among the countries sharing the basin. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação

Desenvolvimento e caracterização de filme polimérico produzido a partir de gelatina de pele detilápia (Oreochromis niloticus) contendo lignina encapsulada

2026-09-03T05:08:59Z

Título: Desenvolvimento e caracterização de filme polimérico produzido a partir de gelatina de pele detilápia (Oreochromis niloticus) contendo lignina encapsulada Autor(es): Eberhart, Markus Rafael Carvalho Primeiro Orientador: Paz, Marcelo Fossa da Abstract: The development of biodegradable films from agro-industrial waste represents an alternative to conventional synthetic polymers. This study aimed to develop and characterize films based on gelatin obtained from Nile tilapia (Oreochromis niloticus) skin, containing lignin encapsulated by pectin (LP). The gelatin showed an extraction yield of approximately 16%. The films were produced via casting using formulation M4, composed of 5% gelatin, 1% glutaraldehyde, and 0.6% glycerin, as well as formulations M4 + LP 0.2% and M4 + LP 1.0%. Colorimetric and mechanical properties, solubility, biodegradation, and spectroscopic characteristics (UV-Vis diffuse reflectance, fluorescence, and FTIR) were evaluated. Quantitative data were analyzed using descriptive statistics, ANOVA, and Tukey's test, with a significance level of 5%. Tensile strength was 8.00 MPa for M4, 7.68 MPa for M4 + LP 0.2%, and 10.04 MPa for M4 + LP 1.0%, demonstrating an increase of approximately 25.5% in the formulation with the highest LP concentration. Conversely, elongation decreased from 87.04% to 40.88% and 16.75%, respectively, indicating increased rigidity and reduced matrix mobility. The average mass gain in the permeability test was 0.1579, 0.1549, and 0.1212 g·day⁻¹ for M4, M4 + LP 0.2%, and M4 + LP 1.0%, respectively. Water vapor permeability decreased from 4.0062 to 3.9301 and 3.0758 g·mm·m⁻²·day⁻¹·kPa⁻¹, corresponding to a reduction of approximately 23.2% for M4 + 1.0% LP. Average solubility showed a slight decrease, from 18.83 ± 1.78% to 18.27 ± 2.07% and 17.94 ± 0.83%, with no significant difference according to ANOVA (F = 0.374; p = 0.695). In the soil burial test, the films lost integrity before a complete mass curve could be obtained, with disintegration and the presence of mycelium observed by the sixth day. Regarding diffuse reflectance, the average value in the UV region dropped from 6.12% to 4.87% and 2.05%. The maximum Kubelka–Munk function increased from 9.02 to 11.22 and 28.42, representing a 214.9% increase for the formulation with 1.0% LP and indicating greater ultraviolet radiation attenuation. In fluorescence analysis, peak maxima remained between 495.5 and 497.0 nm, but intensity decreased from 3198 a.u. to 1859 and 1301 a.u., corresponding to quenching rates of 41.87% and 59.32%. The full width at half maximum (FWHM) ranged from 76.6 nm for the control to 84.1 nm for M4 + 1.0% LP. FTIR analysis confirmed characteristic bands for gelatin, lignin, and pectin without the formation of new detectable functional groups, suggesting predominantly intermolecular interactions. The pectin exhibited an estimated degree of methylation between 40% and 46%, classifying it as low-methoxyl pectin. It is concluded that M4 + 1.0% LP exhibited the best performance regarding barrier properties, mechanical strength, and optical protection, albeit with a marked loss of flexibility. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação