Doutorado em Agronomia (EA)

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http://200.137.215.59/tede/handle/tde/181

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Navegando Doutorado em Agronomia (EA) por Por Área do CNPQ "CIENCIAS AGRARIAS::AGRONOMIA"

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    Fertilização nitrogenada como ferramenta para mitigação de efeitos do déficit de radiação solar no arroz irrigado
    (Universidade Federal de Goiás, 2023-09-06) Carvalho, Renata de Castro Marques; Moraes, Moemy Gomes de; http://lattes.cnpq.br/5678716451015561; Heinemann, Alexandre Bryan; http://lattes.cnpq.br/0452123469996239; Heinemann, Alexandre Bryan; Stone, Luís Fernando; Santos, Marcos Paulo dos; Silva, Rodrigo de Souza; Silva, Elaine Fernanda da
    Rice is part of the routine diet of the Brazilian population. Worldwide, it is considered one of the species with the greatest potential for combating hunger. Nitrogen is the nutrient most required by the rice crop. Solar radiation is one of the elements of the climate that most affects crop productivity. In Brazil, rice is grown in different regions, whose locations have a different supply of solar radiation throughout the cycle. This is one of the factors that explains the differences in productivity between regions. Some studies have shown that the supply of nitrogen as a top dressing minimizes the damage caused by solar radiation deficit in irrigated rice. In view of the above, the aim of this study was to determine the impact of the solar radiation deficit on two cultivars of irrigated rice and to investigate whether the supply of nitrogen minimizes the effects caused by this deficit. Two field trials were conducted for the 2019/2020 and 2020/2021 harvests. The work was carried out at the Palmital Farm experimental station, belonging to Embrapa Rice & Beans, in the municipality of Goianira-Goiás. The experimental design was randomized blocks, with four replications. The treatments were arranged in a subdivided plot design, with shading as the main plot, the nitrogen dose as the subplot and the cultivars as the sub-sub-plots. The cultivars studied were BRS Catiana and IRGA 424 RI. The nitrogen source used was urea, at doses of 50 kg ha-1 of N (applied just once, at the V2 stage) and 180 kg ha-1 of N (spread over three seasons, V2; V3 and V6, with the respective doses of 50; 50 and 80 kg ha-1 of N). The light-restricted plots were covered with a black propylene screen with an attenuation capacity of 30% of global solar radiation, which was installed at the start of flowering (R4) and remained in place until physiological maturity (R9). Fifteen days after the shading was installed, the plants' gas exchange was assessed using an infrared gas analyzer. At the same time, plant samples were taken for analysis of non-structural carbohydrates (NSC) and total nitrogen content. At harvest time, a 1.0 m row was sampled for analysis of yield components. Yield was obtained by harvesting 10 m of the row. Whole grain yield was assessed by processing a 100 gram sample from each experimental plot. The data was submitted to analysis of variance and the means were compared using the Tukey test (p<0,05). Shading reduced the concentration of non-structural carbohydrates in the leaf and stem of the cultivars in the shaded condition. The nitrogen content in the plant was reduced under conditions of light restriction. Gas exchange (net photosynthesis, stomatal conductance, internal CO2 concentration and transpiration) was affected by the availability of solar radiation. Under shaded conditions, there was a lower yield of whole grains. Increased nitrogen application allowed for a recovery in gas exchange, non-structural carbohydrates, nitrogen content in the plant, productivity and whole grain yield, under conditions of limited solar radiation. The IRGA 424 RI cultivar had a greater ability to adjust in the shaded condition compared to BRS Catiana, which implied higher productivity in this condition. In the unshaded condition and at the highest dose of N (180 kg ha-1), the BRS Catiana cultivar showed higher productivity than IRGA 424 RI. Applying nitrogen as a top dressing is a management strategy that can be applied to minimize the impact of solar radiation deficit on irrigated rice crops.
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    Isolamento, caracterização e aplicação da fração proteica de grão-de-bico (Cicer arietinum L.) extraída por método alcalino assistido por ultrassom
    (Universidade Federal de Goiás, 2024-04-04) Prado, Priscylla Martins Carrijo; Caliari, Márcio; Soares Júnior, Manoel Soares; http://lattes.cnpq.br/0920319108540253; Soares Júnior, Manoel Soares; Cavalcante, Rodrigo Barbosa Monteiro; Oliveira, Aryane Ribeiro; Mársico, Eliane Teixeira; Santos, Elaine Alves dos
    The objective of this research was to test the alkaline method followed by isoelectric precipitation in the extraction of protein from whole chickpea flour, aiming to optimize processing time and improve the technological properties of protein extracts, as well as to characterize and apply these extracts in vegetable burgers. For protein extraction, a BoxBehnken design was used, varying the solid-to-liquid ratio (1:05; 1:10; 1:15), pH (7.0; 9.5; and 12.0), and sonication time (10; 25; and 40 min) at three levels, totaling 15 assays, plus three repetitions at the central point. The most desirable experiment (ED - solid-to-liquid ratio 1:12.5 g mL-1, pH 9.5, and 40 min time) was compared to the extract from the control experiment (EC) and three other experimental conditions evaluated for their technological, chemical, physicochemical, and morphological properties. Subsequently, vegan burgers were formulated with different plant sources for comparison of technological, chemical, and textural properties with a commercial one in a first assay. Then, ED was used in the formulations of vegan burgers at different levels of substitution of whole chickpea flour by chickpea protein extract, generating a second assay, which also compared the use of two natural dyes (açaí and beetroot). The alkaline extraction method assisted by ultrasound did not increase yield but reduced extraction time and improved functional properties, indicating that the extracted protein fraction has potential for use in the development of new food products. In the burger assay, there was an increase of about 24% in yield and moisture retention, and up to 72% in oil retention when comparing burgers from different plant sources to the commercial one, although the latter stood out in protein and fiber composition, providing texture quality. In the assay with the addition of protein extract, there was an increase of up to 2% in yield and about 52% in oil retention. However, natural dyes contributed to increasing fiber content by up to 11%, surpassing that of the commercial one. Further studies with different extraction conditions can be conducted to try to improve the properties of chickpea protein extracts, and enrichment with higher percentages of chickpea protein or combination with other protein extracts can be tested to increase the protein content of vegetable burgers. However, the extracts are viable alternatives for application in food, as the formulations produced in this research indicate a good alternative for those seeking plant-based products.