Principais Coleções do Repositório
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tese
Avaliação do comportamento sensorial de edulcorantes de estévia com diferentes composições químicas aplicados em mousse de chocolate vegano
(Universidade Federal de Lavras, 2025-10-29) Freire, Tassyana Vieira Marques; Pinheiro, Ana Carla Marques; Abreu, Luiz Ronaldo de; Souza, Vanessa Rios de; Bastos, Sabrina Carvalho; Lago, Rafael Carvalho do
Evidence linking excessive sugar consumption to obesity and diabetes has driven changes in dietary habits. At the same time, consumer preference for natural ingredients and uncertainties regarding the safety of artificial sweeteners have increased interest in natural alternatives. Among these, steviol glycosides (stevia) obtained from Stevia rebaudiana stand out, although their acceptance must be evaluated in real matrices. Therefore, the objective of this study was to evaluate the replacement of sucrose with five commercial stevia samples (A, B, C, D, and E) in vegan chocolate mousse, integrating sensory and analytical methods to guide the technological selection of sweeteners. Initially, for comparative studies, 22 panelists were selected and trained according to ISO 8586/8589 (sequential Wald screening) and performed Magnitude Estimation using 10% sucrose as reference. The log-concentration vs. log-intensity relationships followed Stevens’ Power Law for both sucrose and stevia samples (R² ≥ 0.9605). Equivalent concentrations were <0.15% w/w and sweetness potency ranged from 67.71× to 332.28×. HPLC characterization revealed compositional heterogeneity (Rebaudiosides M, D, C, and rubusoside), and PCA (PC1 = 50%; PC2 = 39%) showed a positive association between sweetness potency and RM (Stevia D: high RM) and a negative association with rubusoside (Stevia B: higheer R and lower potency). Temporal sensory results (TDS) showed that while sucrose exhibited the expected TDS profile (dominant and prolonged sweetness), stevia samples presented shorter curves, unstable dominance, and rapid transitions among attributes. This behavior reflects the complexity of the matrix and the chemical–sensory interactions between bitter compounds and steviol glycosides. Matrix effects emphasize that the sensory performance of natural sweeteners must be interpreted in the context of the final application, as texture, fat content, and cocoa phenolic compounds may alter perception kinetics, enhancing bitterness perception of less glycosylated steviol glycosides (RC and R), as seen in samples with Stevia B and E, and interfering with the sensory dominance of compounds associated with dominant sweetness profile and without undesirable residual (RM and RD), even in samples with high sweetening power. In conclusion, although steviol glycosides are high-intensity sweeteners, their sweetness potency and temporal sensory profiles vary according to their chemical composition and interactions within the food matrix. These findings reinforce the importance of controlling the chemical composition of glycoside blends to minimize undesirable aftertastes and achieve sensory balance. The results provide valuable insights for the food industry to support sucrose replacement strategies in different products.
tese
Biological control of common bacterial blight and reduction of transmission of Xanthomonas phaseoli pv. phaseoli to bean seeds
(Universidade Federal de Lavras, 2026-06-29) Gontijo, Guilherme Foschetti; Souza, Ricardo Magela de; Siqueira, Carolina da Silva; Siqueira, Carolina da Silva; Carvalho, Claudine Marcia; Machado, José da Cruz; Botelho, Deila Magna dos Santos
Common bacterial blight (CBC), caused by Xanthomonas phaseoli pv. phaseoli (Xpp), is one of the most important diseases affecting common bean crops, with its incidence resulting in annual yield losses. The primary means of pathogen dissemination is through the association of the bacterium with bean seeds, which transmit the pathogen to emerging plants and subsequently lead to disease development. The limited availability of effective control methods highlights the need to develop alternative strategies integrated into crop management systems. Biological control of plant diseases is an efficient method and has shown positive results against several phytopathogens in bean cultivation. Therefore, the objective of this study was to evaluate the effects of spraying endophytic bacteria on bean plants for the control of common bacterial blight. Bacterial isolates obtained from bean seeds and one isolate from tomato (UFLA22) were selected for use as biological control agents, along with an Xpp isolate also obtained from bean seeds. Experiments were conducted under laboratory and greenhouse conditions in a randomized block design. The antibiosis effect of the selected bacteria against the Xpp isolate, disease severity, plant height and weight, phenolic compound contents, and phenylalanine ammonia-lyase (PAL) activity after treatment were evaluated. All evaluated isolates inhibited Xpp growth in vitro. Isolates G35, G37, G40, and UFLA22 showed greater effectiveness in controlling common bacterial blight, with isolate UFLA22 being the most efficient. Isolates G33, and UFLA22 contributed to the increase of plant weight in diseased plants, exceeding the values observed in the inoculated control and in the healthy control. Phenolic compound contents and PAL activity were higher in treatments with isolates G40 and UFLA22 compared with the inoculated control. Isolates G40 and UFLA22 reduced the transmission of Xpp to bean seeds, being recovered from seeds when applied on R6. These results demonstrate that bacteria isolated from bean seeds may be effective in controlling CBC.
dissertação
Pegada de carbono e custeio do ciclo de vida na produção de café orgânico
(Universidade Federal de Lavras, 2026-06-29) Hamasaki, Paulo Seiiti Araújo; Terra, Marcela de Castro Nunes Santos; https://orcid.org/0000-0003-4646-2414; Chiodi, Rafael Eduardo; https://orcid.org/0000-0002-5462-6856; Teixeira, Elaine Cristina; https://orcid.org/0000-0001-5215-8238
The growing demand for sustainable agricultural systems has driven the development of tools capable of simultaneously assessing the environmental and economic performance of productive activities. In this context, organic coffee farming stands out as a potential alternative for reducing environmental impacts, adding value to agricultural products, and promoting sustainability in rural areas. This study aimed to evaluate the environmental and economic performance of organic coffee production (Coffea arabica L.) in the municipality of Maria da Fé, Minas Gerais, Brazil, through the preparation of a greenhouse gas (GHG) inventory, carbon footprint quantification, and the application of the Life Cycle Costing (LCC) methodology. The research was conducted on a certified organic and specialty coffee farm covering 2 hectares during the period from 2020 to 2025. The emissions inventory was developed using the GHG Protocol Coffee Production Tool, specifically designed for Brazilian coffee-growing conditions, considering direct and indirect emissions as well as carbon removal processes associated with plant biomass and land-use change. The economic assessment was carried out using Life Cycle Costing, employing financial indicators such as Net Present Value (NPV), Internal Rate of Return (IRR), and Discounted Payback Period. The results showed cumulative emissions of 19.92 t CO₂e over the evaluated period, corresponding to a gross carbon footprint of 1.92 kg CO₂e kg⁻¹ of coffee produced. However, when carbon removals resulting from biomass growth and the conversion of a former pasture area into a coffee plantation were considered, a cumulative net balance of -99.54 t CO₂e was observed, resulting in a net carbon footprint of -9.59 kg CO₂e kg⁻¹ of coffee. These findings demonstrate that the production system acted as a net carbon sink throughout the entire study period. From an economic perspective, the activity presented a Net Present Value of R$ 9,876.45, an Internal Rate of Return of 17.61% per year, and a Discounted Payback Period of 3.45 years, indicating financial viability despite the substantial initial investments required for plantation establishment and maintenance of organic certification. The integration of environmental and economic indicators demonstrated that organic coffee production can reconcile economic profitability with climate change mitigation, reinforcing its potential as a sustainable development strategy for Brazilian coffee farming. In addition to contributing to income generation and strengthening family farming, the results provide technical support for farmers, cooperatives, and policymakers involved in lowcarbon agriculture initiatives. The study expands current knowledge regarding the relationship between environmental sustainability and economic viability in coffee production, serving as a reference for future research and for the development of more resilient, competitive, and environmentally responsible production systems aligned with contemporary sustainability challenges.
tese
Variações funcionais em diferentes fisionomias vegetacionais no Brasil
(Universidade Federal de Lavras, 2026-04-30) Oliveira, Fernanda; Santos, Rubens Manoel dos; https://orcid.org/ 0000-0002-4075-462X; Silva, Orivaldo Benedito da; https://orcid.org/0000-0001-5734-8196; Lira, Marinês Ferreira Pires; https://orcid.org/0000-0003-0660-5775; Araújo, Felipe de Carvalho; https://orcid.org/0000-0003-0210-8763; Sene, André Maciel da Silva; https://orcid.org/0000-0003-3469-2810
Brazil, the largest country on the South American continent, has a wide distribution of distinct environments within its phytogeographic domains, including the Amazon, Caatinga, Cerrado, Atlantic Forest, Pantanal, and Pampas, each comprising structurally and functionally different forest formations. It is of great importance for understanding the structural and functional patterns of vegetation. In this sense, studies with a functional and anatomical approach to plant species become an extremely important tool for providing a scenario of essential adaptations for the survival of species in constantly changing environmental and climatic conditions. Thus, the objective of this research was to characterize the functional and anatomical responses of tree species existing in the phytogeographic domains of Minas Gerais, Bahia, and Piauí, aiming to identify the ecological strategies that influence adaptive success in different tropical forests with distinct environmental conditions. Collections were carried out between 2021 and 2025 in 34 areas with plots distributed across different vegetation formations in Brazil. Subsequently, the samples were measured and analyzed, and the data were deposited in the database of the Phytogeography and Evolutionary Ecology Laboratory at UFLA. The research results generally show that tree species are responding to environmental and climatic changes with different ecological strategies through anatomical and functional characteristics, along an environmental gradient across distinct phytophysiognomies. This article presents a more comprehensive approach, showing the anatomical and functional variation of each individual in the different physiognomies of tropical and savanna forests in Brazil, and the ecological strategies employed. It was observed that species from drier environments presented characteristics related to resource conservation and greater resistance to water stress, demonstrated by dry matter content and vessel density. In relation to species from more humid environments, the analyses indicated characteristics related to greater efficiency in resource acquisition, indicated by specific leaf area and chlorophyll parenchyma. Thus, the research reinforces the importance of integrating studies between functional anatomy and plant ecology for understanding species distribution patterns and ecosystem functioning, emphasizing the importance of environmental gradients in structuring plant communities.
dissertação
Índice de curva ótima para implantação de lavouras cafeeiras
(Universidade Federal de Lavras, 2026-08-21) Souza, Fernando Henrique de; Faria, Rafael de Oliveira; Ferraz, Gabriel Araujo e Silva; https://orcid.org/0000-0001-6403-2210; Barros, Murilo Machado de; https://orcid.org/0000-0003-0378-4800; Silva, Flávio Castro da; https://orcid.org/0000-0003-1366-9806
Coffee cultivation is extremely important to the Brazilian agricultural economy, requiring the adoption of techniques that increase productivity and reduce operating costs. The use of highaccuracy elevation data is essential for the efficient planning of mechanized planting rows, particularly in mountainous regions such as southern Minas Gerais, Brazil. This study aimed to develop an Optimal Curve Index (OCI) for designing coffee planting rows by considering mechanization variables, topographic characteristics, and the optimization of the number of transplanted seedlings per hectare. The research involved analyzing mechanized areas, determining optimal curvature and slope parameters, and establishing practices to prevent plant damage caused by machinery traffic during agricultural operations. Technologies for acquiring topographic data were compared, including a LiDAR sensor mounted on a remotely piloted aircraft (DJI Matrice 350 RTK equipped with a Zenmuse L2) and GNSS receivers using RTK correction. LiDAR elevations were processed using the hgeoHNOR2020 geoid model and referenced to the SIRGAS 2000 / UTM Zone 23S coordinate system. The initial analysis indicated that the data were not normally distributed, as confirmed by the Shapiro–Wilk test (p = 2.79 × 10−21 for GNSS and p = 2.97×10−21 for LiDAR). The Wilcoxon test revealed a statistically significant difference between the measurements, with a mean bias of 1.56 m, indicating the need for vertical correction of the GNSS data. The OCI model, validated through Monte Carlo simulations, showed that tractor–implement combinations can negotiate tighter curves, whereas self-propelled harvesting imposes stricter constraints due to the geometry of the harvester. The harvesting-tunnel length adopted in the model was 3.66 m, resulting in an absolute critical radius of 6.61 m. Depending on the local slope, the harvester required minimum safe radii greater than 20 m to operate without mechanical collisions with coffee plant trunks, drastically reducing overall operational suitability in fields with sharp curves. It was concluded that the OCI, which can be supplied with data obtained affordably from sensors already installed on agricultural machinery, is a feasible tool for guiding planting-row design in the field and reducing the need for future physical interventions in coffee plantations