Peanut production has been decreasing in Senegal over the past decades for historical, political, economic and environmental reasons. One of the solutions proposed by recent Senegalese administrations is to increase production through agricultural research and the development of peanut varieties that are adapted to the environmental constraints in Senegal. The last variety developed is La Fleur 11, which is very drought tolerant. The purpose of the study is to assess the economic impact of research on La Fleur 11 on the Senegalese economy through an ex-ante evaluation of the net social benefits from the adoption of this new variety. In order to fulfill this objective, an economic surplus analysis is conducted within the framework of a partial equilibrium model. Results indicate that the net social benefits from the adoption of La Fleur 11 are positive. Assuming that all peanut supply is sold to SONACOS at a producer base price and that research evaluation is conducted at the farm-level, Consumers (SONACOS) are the main beneficiaries from research. Their benefits are on average 6 times producers' (farmers). The research-induced increase in the government cost of the subsidy represents 84 percent on average of consumers' and producers' benefits; the research-induced increase in net social welfare represents 16 percent on average of consumers' and producers' benefits. The internal rate of return averages around 43 percent. When peanut markets are disaggregated, research benefits consumers (SONACOS) 3 times more than producers (farmers) at the farm level. Most of producers' benefits come from farm household consumption (47 percent of total farm-level benefits) and most of consumers' benefits come from the official seed market. At the SONACOS-level where peanut oil and cakes are exported, research benefits producers (SONACOS) only; consumers (rest of the world) do not benefit from research at this level. The IRR is more likely to be about 42 percent. This study suggests that future investments in agricultural research in Senegal can result in a positive economic impact provided that other actions are undertaken regarding extension, credit, and input distribution in order to enhance adoption and take advantage of the yield potential of the new peanut varieties. Also, this study provides a procedure of research evaluation for future use in Senegal and West Africa. / Master of Science

Atualmente, o termo sustentabilidade vem ganhando destaque dentro das atividades agrícolas e para a produção animal em pastagens não é diferente. As leguminosas forrageiras são conhecidas por algumas características peculiares como grande capacidade de fixação do nitrogênio atmosférico e elevado valor nutritivo, surgindo assim como uma alternativa viável nesse novo modelo de produção. Entretanto, muitas vezes práticas de manejo inadequadas acabam não permitindo a exploração do potencial dessas espécies, levando-as ao desuso. Dessa forma, conhecer a resposta de plantas (alterações em forma e função) a intensidades de pastejo é imprescindível para permitir a idealização de estratégias de manejo eficientes que possam contribuir para a otimização do processo produtivo em sistemas pastoris. Este trabalho fez parte de uma série de experimentos delineados com o propósito de avaliar aspectos gerais de crescimento e desenvolvimento do amendoim forrageiro sob pastejo e suas implicações sobre a produção de forragem e potencial de consumo pelos animais. Seu objetivo específico foi avaliar as características produtivas de Arachis pintoi cv. Belmonte submetido a intensidades de pastejo sob lotação contínua. O experimento foi conduzido na Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, de janeiro a dezembro de 2013. Os tratamentos corresponderam a intensidades de pastejo determinadas por alturas de manejo do pasto (5, 10, 15 e 20 cm), e foram alocados às unidades experimentais (piquetes de aproximadamente 200 m²) segundo delineamento de blocos completos casualizados, com quatro repetições. Foram caracterizadas e determinadas as seguintes variáveis-resposta: índice de área foliar, ângulo da folhagem, interceptação luminosa do dossel, massa de forragem e sua composição botânica e morfológica, número e massa de nódulos radiculares, massa de raízes e acúmulo de forragem. As intensidades de pastejo promoveram alterações no crescimento e desenvolvimento do Arachis pintoi cv. Belmonte. Pastos manejados com intensidade de pastejo mais leniente (15 e 20 cm) apresentaram maior índice de área foliar, ângulo da folhagem, massa de forragem, porcentagem de plantas invasoras e taxa de acúmulo de forragem (exceto no inverno). Em contrapartida, pastejos severos (5 e 10 cm) proporcionaram maiores valores de porcentagem de folíolos e pecíolos, relação folíolo/estolão, número e massa de nódulos, massa de raízes e taxa de acúmulo de forragem durante o inverno. A intensidade de pastejo não afetou o peso médio dos nódulos, somente o seu número e massa total. Outros aspectos produtivos apresentaram efeitos isolados de época do ano como porcentagem de estolão e de material morto, com maiores valores registrados no verão e no inverno, respectivamente. Estolões assim como folhas (folíolos e pecíolos) corresponderam às principais estruturas na determinação do crescimento das plantas, tendo sido afetados de forma direta pela intensidade de pastejo e época do ano. A intensidade de pastejo interferiu com a relação parte aérea/raízes, de forma que maior massa de raízes e de nódulos foram registradas nos pastos manejados a 5 e 10 cm e o maior IAF, interceptação de luz e acúmulo de forragem foram registrados nos pastos manejados a 15 e 20 cm. O fato indica uma relação de compensação entre número e massa de nódulos/raízes e IAF controlando o acúmulo de forragem, revelando grande plasticidade fenotípica potencial dessa planta forrageira e potencial de uso em pastagens. / In recent years the term sustainability is becoming increasingly important in agriculture, including animal production from pastoral systems. Forage legumes are known for some particular characteristics like large capacity for capturing atmospheric nitrogen and high nutritive value of the produced herbage, and for that reason is being considered as a viable alternative in this new production model. However, inadequate management practices often result in no realisation and exploitation of their production potential, resulting in low use of these plant species. For that reason, understanding of plant responses (modifications in form and function) to intensities of grazing is essential for allowing planning of efficient management practices aiming at optimising productivity in pastoral systems of animal production. This study was part of a series of experiments conceived with the purpose of evaluating general aspects of growth and development of forage peanut under grazing and their implications to herbage production and potential of herbage intake by grazing animals. The specific objective was to evaluate the agronomic characteristics of Arachis pintoi cv. Belmonte subjected to intensities of grazing under continuous stocking. The experiment was carried out at Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, from January to December 2013. Treatments corresponded to four intensities of grazing characterised by the sward management heights of 5, 10, 15 and 20 cm. These were allocated to the experimental units (200 m2 paddocks) according to a randomised complete block design, with four replications. The following response variables were evaluated: sward leaf area index (LAI), foliage angle, canopy light interception (LI), herbage mass and its morphological and botanical composition, number and mass of root nodules, root mass and herbage accumulation. The grazing intensities interfered with growth and development of Arachis pintoi cv. Belmonte. Swards managed at 15 and 20 cm showed higher LAI, foliage angle, herbage mass, percentage of weeds and herbage accumulation rates (except in winter) than those managed at 5 and 10 cm. On the other hand, swards managed at 5 and 10 cm showed higher percentage of leaf, leaf-to-stolon ratio, number and mass of root nodules, root mass and winter herbage accumulation rates. Grazing intensity did not affect average nodule weight, only nodule number and total mass. Other productive aspects revealed isolated effects of season of the year like percentages of stolon and dead material, with larger values recorded during summer and winter, respectively. Stolons as well as leaves corresponded to the main structures determining plant growth, and were directly affected by grazing intensity and season of the year. Grazing intensity interfered with the shoot-to-root ratio, with larger root and nodule mass being recorded on swards managed at 5 and 10 cm and larger LAI, LI and herbage accumulation recorded on swards managed at 15 and 20 cm. The fact indicates a compensating relationship between number and mass of nodules/roots and LAI controlling herbage accumulation, highlighting the large potential phonotypical plasticity of this forage plant and potential of use in pastures.

O presente experimento de laboratório foi realizado no Departamento de Ciência do Solo da ESALQ/USP, em Piracicaba, SP, com o objetivo de avaliar o efeito da presença de diferentes resíduos vegetais na superfície do solo sobre as perdas de amônia por volatilização decorrentes da aplicação de uréia em três doses. Foram utilizadas amostras da camada 0-0,20m de um Nitossolo Vermelho Eutroférrico do município de Piracicaba, SP. Os tratamentos constaram de arranjo fatorial com três repetições envolvendo quatro doses de uréia (0, 60, 120 e 180 mg dm-3 de N), aplicadas na superfície da terra, e quatro formas de cobertura da terra: sem cobertura e com cobertura constituída de fragmentos de folhas de plantas de milho, cana-de-açúcar e amendoim forrageiro, igualmente aplicados na superfície na quantidade de 29g de matéria seca por frasco (equivalente a 5 Mg ha-1). A volatilização de amônia foi avaliada em frascos de plástico de 1,6 L de capacidade, fechados, contendo 0,4 kg de terra umedecida e, para captar a amônia volatilizada, um disco de papel de filtro tratado com 1 mL de H2SO4 de concentração variando de 0,05 a 0,5 mol L-1. Esse disco era substituído diariamente, sendo o ácido remanescente no filtro exposto à amônia, titulado com NaOH 0,02 mol L-1 na presença de indicador bromocresol verde. Ao final do período experimental de 40 dias, amostras da camada superficial (0-0,05m) de terra dos frascos foram coletadas com amostrador especial e submetidas à determinação do pH em CaCl2 0,01 mol L-1. Os picos de máxima perda de amônia por volatilização ocorreram no 3º e no 12º dia após a aplicação da uréia, não havendo efeito dos resíduos culturais sobre a distribuição das perdas ao longo do tempo. As perdas de amônia aumentaram com o aumento da dose de uréia aplicada. Nas terras sem cobertura e naquelas contendo resíduos de milho e de amendoim forrageiro os aumentos foram mais expressivos para as doses menores (60 e 120 mg dm-3 de N-uréia), enquanto nas terras com restos de cana-de-açúcar os maiores aumentos ocorreram para a dose mais alta (180 mg dm-3 de N-uréia). A presença de restos de cultura de amendoim forrageiro na superfície do solo aumentou a quantidade de amônia volatilizada das terras tratadas ou não com uréia, enquanto a de restos de cultura de cana-de-açúcar reduziu a quantidade volatilizada. Os restos de cultura de milho exerceram pouca influência nas perdas de NH3 por volatilização. O pH da camada superficial das terras aumentou em mais de duas unidades com a aplicação de uréia e dos resíduos vegetais. / A laboratory experiment was carried out at the University of São Paulo, Piracicaba campus, Brazil, in order to evaluate how the presence of different plant residues on soil surface will affect ammonia volatilization losses from urea fertilizer applied on soil surface in three rates. Samples from 0-0.2m layer of a ferric Red Latosol located in Piracicaba, State of São Paulo, Brazil, were used in the study. Treatments consisted of a factorial arrangement with three replicates involving four rates of urea (0, 60, 120 and 180 mg dm-1 of N), applied at soil surface and four forms of soil cover: with no cover and with cover consisted of leaf fragments of corn, sugar-cane and peanut plants also applied on the surface at the rate of 29 g of dryed material per flask (equivalent to 5 Mg per hectare). Ammonia volatilization was measured in closed 1.6 L flasks containing 0.4 kg of moistened soil sample and, to capture NH3, a filter paper disk treated with 1 mL of H2SO4 of concentration varying from 0.05 to 0.5 mol L-1. The paper filter was substituted every day and the remaining acid in the exposed filter was titrated with NaOH 0.02 mol L-1 in the presence of bromocresol green. At the end of the experimental period of 40 days, samples of the surface layer (0-0.05 m) of the soil in the flasks were collected using a special sampler and subjected to determination of the pH in CaCl2 0.01 mol L-1. Maximum volatilization occurred at the 3rd and the 12th day of urea application and no influence was observed of the plant residues on the distribution of the losses during the experimental period. Ammonia losses increased with the rate of urea application. For the bare soil samples and for samples covered with corn and peanut residues, these increases were more evident when urea was applied at the smaller rates (60 and 120 mg dm-1 of urea-N), whereas for samples covered with sugar-cane residues, increases were higher when the higher rate (180 mg dm-1 of urea-N) was used. Covering the soil with peanut residues increased the amount of volatilized ammonia in the samples treated and not treated with urea, while covering with sugar-cane residues reduced the volatilization losses. Corn residues showed to have only small influence on ammonia loss. The pH at the surface of the soil samples increased more than two units as the result of urea and plant residues application.

Atualmente, o termo sustentabilidade vem ganhando destaque dentro das atividades agrícolas e para a produção animal em pastagens não é diferente. As leguminosas forrageiras são conhecidas por algumas características peculiares como grande capacidade de fixação do nitrogênio atmosférico e elevado valor nutritivo, surgindo assim como uma alternativa viável nesse novo modelo de produção. Entretanto, muitas vezes práticas de manejo inadequadas acabam não permitindo a exploração do potencial dessas espécies, levando-as ao desuso. Dessa forma, conhecer a resposta de plantas (alterações em forma e função) a intensidades de pastejo é imprescindível para permitir a idealização de estratégias de manejo eficientes que possam contribuir para a otimização do processo produtivo em sistemas pastoris. Este trabalho fez parte de uma série de experimentos delineados com o propósito de avaliar aspectos gerais de crescimento e desenvolvimento do amendoim forrageiro sob pastejo e suas implicações sobre a produção de forragem e potencial de consumo pelos animais. Seu objetivo específico foi avaliar as características produtivas de Arachis pintoi cv. Belmonte submetido a intensidades de pastejo sob lotação contínua. O experimento foi conduzido na Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, de janeiro a dezembro de 2013. Os tratamentos corresponderam a intensidades de pastejo determinadas por alturas de manejo do pasto (5, 10, 15 e 20 cm), e foram alocados às unidades experimentais (piquetes de aproximadamente 200 m²) segundo delineamento de blocos completos casualizados, com quatro repetições. Foram caracterizadas e determinadas as seguintes variáveis-resposta: índice de área foliar, ângulo da folhagem, interceptação luminosa do dossel, massa de forragem e sua composição botânica e morfológica, número e massa de nódulos radiculares, massa de raízes e acúmulo de forragem. As intensidades de pastejo promoveram alterações no crescimento e desenvolvimento do Arachis pintoi cv. Belmonte. Pastos manejados com intensidade de pastejo mais leniente (15 e 20 cm) apresentaram maior índice de área foliar, ângulo da folhagem, massa de forragem, porcentagem de plantas invasoras e taxa de acúmulo de forragem (exceto no inverno). Em contrapartida, pastejos severos (5 e 10 cm) proporcionaram maiores valores de porcentagem de folíolos e pecíolos, relação folíolo/estolão, número e massa de nódulos, massa de raízes e taxa de acúmulo de forragem durante o inverno. A intensidade de pastejo não afetou o peso médio dos nódulos, somente o seu número e massa total. Outros aspectos produtivos apresentaram efeitos isolados de época do ano como porcentagem de estolão e de material morto, com maiores valores registrados no verão e no inverno, respectivamente. Estolões assim como folhas (folíolos e pecíolos) corresponderam às principais estruturas na determinação do crescimento das plantas, tendo sido afetados de forma direta pela intensidade de pastejo e época do ano. A intensidade de pastejo interferiu com a relação parte aérea/raízes, de forma que maior massa de raízes e de nódulos foram registradas nos pastos manejados a 5 e 10 cm e o maior IAF, interceptação de luz e acúmulo de forragem foram registrados nos pastos manejados a 15 e 20 cm. O fato indica uma relação de compensação entre número e massa de nódulos/raízes e IAF controlando o acúmulo de forragem, revelando grande plasticidade fenotípica potencial dessa planta forrageira e potencial de uso em pastagens. / In recent years the term sustainability is becoming increasingly important in agriculture, including animal production from pastoral systems. Forage legumes are known for some particular characteristics like large capacity for capturing atmospheric nitrogen and high nutritive value of the produced herbage, and for that reason is being considered as a viable alternative in this new production model. However, inadequate management practices often result in no realisation and exploitation of their production potential, resulting in low use of these plant species. For that reason, understanding of plant responses (modifications in form and function) to intensities of grazing is essential for allowing planning of efficient management practices aiming at optimising productivity in pastoral systems of animal production. This study was part of a series of experiments conceived with the purpose of evaluating general aspects of growth and development of forage peanut under grazing and their implications to herbage production and potential of herbage intake by grazing animals. The specific objective was to evaluate the agronomic characteristics of Arachis pintoi cv. Belmonte subjected to intensities of grazing under continuous stocking. The experiment was carried out at Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, from January to December 2013. Treatments corresponded to four intensities of grazing characterised by the sward management heights of 5, 10, 15 and 20 cm. These were allocated to the experimental units (200 m2 paddocks) according to a randomised complete block design, with four replications. The following response variables were evaluated: sward leaf area index (LAI), foliage angle, canopy light interception (LI), herbage mass and its morphological and botanical composition, number and mass of root nodules, root mass and herbage accumulation. The grazing intensities interfered with growth and development of Arachis pintoi cv. Belmonte. Swards managed at 15 and 20 cm showed higher LAI, foliage angle, herbage mass, percentage of weeds and herbage accumulation rates (except in winter) than those managed at 5 and 10 cm. On the other hand, swards managed at 5 and 10 cm showed higher percentage of leaf, leaf-to-stolon ratio, number and mass of root nodules, root mass and winter herbage accumulation rates. Grazing intensity did not affect average nodule weight, only nodule number and total mass. Other productive aspects revealed isolated effects of season of the year like percentages of stolon and dead material, with larger values recorded during summer and winter, respectively. Stolons as well as leaves corresponded to the main structures determining plant growth, and were directly affected by grazing intensity and season of the year. Grazing intensity interfered with the shoot-to-root ratio, with larger root and nodule mass being recorded on swards managed at 5 and 10 cm and larger LAI, LI and herbage accumulation recorded on swards managed at 15 and 20 cm. The fact indicates a compensating relationship between number and mass of nodules/roots and LAI controlling herbage accumulation, highlighting the large potential phonotypical plasticity of this forage plant and potential of use in pastures.

O presente experimento de laboratório foi realizado no Departamento de Ciência do Solo da ESALQ/USP, em Piracicaba, SP, com o objetivo de avaliar o efeito da presença de diferentes resíduos vegetais na superfície do solo sobre as perdas de amônia por volatilização decorrentes da aplicação de uréia em três doses. Foram utilizadas amostras da camada 0-0,20m de um Nitossolo Vermelho Eutroférrico do município de Piracicaba, SP. Os tratamentos constaram de arranjo fatorial com três repetições envolvendo quatro doses de uréia (0, 60, 120 e 180 mg dm-3 de N), aplicadas na superfície da terra, e quatro formas de cobertura da terra: sem cobertura e com cobertura constituída de fragmentos de folhas de plantas de milho, cana-de-açúcar e amendoim forrageiro, igualmente aplicados na superfície na quantidade de 29g de matéria seca por frasco (equivalente a 5 Mg ha-1). A volatilização de amônia foi avaliada em frascos de plástico de 1,6 L de capacidade, fechados, contendo 0,4 kg de terra umedecida e, para captar a amônia volatilizada, um disco de papel de filtro tratado com 1 mL de H2SO4 de concentração variando de 0,05 a 0,5 mol L-1. Esse disco era substituído diariamente, sendo o ácido remanescente no filtro exposto à amônia, titulado com NaOH 0,02 mol L-1 na presença de indicador bromocresol verde. Ao final do período experimental de 40 dias, amostras da camada superficial (0-0,05m) de terra dos frascos foram coletadas com amostrador especial e submetidas à determinação do pH em CaCl2 0,01 mol L-1. Os picos de máxima perda de amônia por volatilização ocorreram no 3º e no 12º dia após a aplicação da uréia, não havendo efeito dos resíduos culturais sobre a distribuição das perdas ao longo do tempo. As perdas de amônia aumentaram com o aumento da dose de uréia aplicada. Nas terras sem cobertura e naquelas contendo resíduos de milho e de amendoim forrageiro os aumentos foram mais expressivos para as doses menores (60 e 120 mg dm-3 de N-uréia), enquanto nas terras com restos de cana-de-açúcar os maiores aumentos ocorreram para a dose mais alta (180 mg dm-3 de N-uréia). A presença de restos de cultura de amendoim forrageiro na superfície do solo aumentou a quantidade de amônia volatilizada das terras tratadas ou não com uréia, enquanto a de restos de cultura de cana-de-açúcar reduziu a quantidade volatilizada. Os restos de cultura de milho exerceram pouca influência nas perdas de NH3 por volatilização. O pH da camada superficial das terras aumentou em mais de duas unidades com a aplicação de uréia e dos resíduos vegetais. / A laboratory experiment was carried out at the University of São Paulo, Piracicaba campus, Brazil, in order to evaluate how the presence of different plant residues on soil surface will affect ammonia volatilization losses from urea fertilizer applied on soil surface in three rates. Samples from 0-0.2m layer of a ferric Red Latosol located in Piracicaba, State of São Paulo, Brazil, were used in the study. Treatments consisted of a factorial arrangement with three replicates involving four rates of urea (0, 60, 120 and 180 mg dm-1 of N), applied at soil surface and four forms of soil cover: with no cover and with cover consisted of leaf fragments of corn, sugar-cane and peanut plants also applied on the surface at the rate of 29 g of dryed material per flask (equivalent to 5 Mg per hectare). Ammonia volatilization was measured in closed 1.6 L flasks containing 0.4 kg of moistened soil sample and, to capture NH3, a filter paper disk treated with 1 mL of H2SO4 of concentration varying from 0.05 to 0.5 mol L-1. The paper filter was substituted every day and the remaining acid in the exposed filter was titrated with NaOH 0.02 mol L-1 in the presence of bromocresol green. At the end of the experimental period of 40 days, samples of the surface layer (0-0.05 m) of the soil in the flasks were collected using a special sampler and subjected to determination of the pH in CaCl2 0.01 mol L-1. Maximum volatilization occurred at the 3rd and the 12th day of urea application and no influence was observed of the plant residues on the distribution of the losses during the experimental period. Ammonia losses increased with the rate of urea application. For the bare soil samples and for samples covered with corn and peanut residues, these increases were more evident when urea was applied at the smaller rates (60 and 120 mg dm-1 of urea-N), whereas for samples covered with sugar-cane residues, increases were higher when the higher rate (180 mg dm-1 of urea-N) was used. Covering the soil with peanut residues increased the amount of volatilized ammonia in the samples treated and not treated with urea, while covering with sugar-cane residues reduced the volatilization losses. Corn residues showed to have only small influence on ammonia loss. The pH at the surface of the soil samples increased more than two units as the result of urea and plant residues application.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-05-02T11:42:47Z No. of bitstreams: 1 2012 - Juliana Scofano Barrabin.pdf: 1875258 bytes, checksum: a222dd8183b171aeac5b500db7dbb482 (MD5) / Made available in DSpace on 2017-05-02T11:42:49Z (GMT). No. of bitstreams: 1 2012 - Juliana Scofano Barrabin.pdf: 1875258 bytes, checksum: a222dd8183b171aeac5b500db7dbb482 (MD5) Previous issue date: 2012-06-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Aflatoxins classified by the World Health Organization as carcinogenic to humans and their intake causes many health injuries, from acute toxicities with liver lesions to hepatocellular carcinoma. Many countries already have regulations regarding these contaminants and the European Union is the most critical in relation to food safety. It has a strict regulation not only in relation to maximum permitted levels of aflatoxins in foods, but also concerning the quality of the analytical methods used to measure such contaminants. In Brazil, the National Agency of Sanitary Surveillance (ANVISA) published the resolution RDC N? 7, February 18th, 2011, providing for maximum permitted levels on mycotoxins in food for human consumption and raw materials, setting every two years the limits of these toxins become smaller, tending to be as strict as the European Union. For these goals to be fulfilled high sensitivity, selectivity and accuracy analytical methodologies are needed. This work aimed to develop an analytical method and to calculate validation parameters for determination of aflatoxin in peanuts using ultra performance liquid chromatography and detection by high-resolution mass spectrometry, method equivalent to the analytical quality standards of the European Union, which are worldwide trend. The developed method showed high selectivity and resolution, allowing the unambiguous qualitative analysis of aflatoxins B1, B2, G1 and G2 in peanuts and fulfilled the most rigorous analytical chromatographic criteria established by the EU. The requirements for a quantitative analysis have been partially achieved. Calibration curves were obtained with good linearity, however, was not possible to fix the sensitivity of the method, compromising the accuracy and quantification of the test. / As aflatoxinas s?o atualmente as micotoxinas mais estudadas no mundo. S?o classificadas pela Organiza??o Mundial da Sa?de como carcinog?nicas para humanos e sua ingest?o causa diversos danos ? sa?de, variando de toxicidades agudas com les?es de f?gado ao carcinoma hepatocelular. Muitos pa?ses j? possuem regulamenta??o quanto a estes contaminantes e a Uni?o Europ?ia (UE) ? uma das comunidades mais cr?ticas em rela??o ? legisla??o das micotoxinas com foco na inocuidade alimentar. Possui uma r?gida legisla??o n?o apenas em rela??o aos limites m?ximos permitidos de aflatoxinas em alimentos, mas tamb?m em rela??o ? qualidade dos m?todos anal?ticos utilizados para medir tais contaminantes. No Brasil, a Ag?ncia Nacional de Vigil?ncia Sanit?ria (ANVISA) publicou a resolu??o RDC N? 7 de 18 de fevereiro de 2011, dispondo sobre limites m?ximos tolerados de micotoxinas em alimentos. Essa resolu??o fixa novos limites para aflatoxinas, al?m de ocratoxina A, desoxinivalenol, fumonisinas, patulina e zearalenona em mat?rias primas e alimentos prontos para consumo, estabelecendo metas para que a cada 2 anos os limites dessas toxinas sejam cada vez menores, tendendo a uma maior rigidez, assim como a UE. Para que essas metas possam ser cumpridas s?o necess?rias metodologias anal?ticas de maior sensibilidade, seletividade e exatid?o. Desta forma o presente trabalho visou desenvolver um m?todo anal?tico e avaliar os par?metros de valida??o necess?rios para determina??o de aflatoxinas em amendoim. Utilizou-se cromatografia l?quida de ultra efici?ncia e detec??o por espectrometria de massas (UPLC-MS) de alta resolu??o, metodologia equiparada aos padr?es de qualidade anal?tica da UE. No m?todo desenvolvido obteve-se de 3 a 7 fragmentos para cada aflatoxina permitindo a an?lise qualitativa inequ?voca das AFB1, AFB2, AFG1 e AFG2 em amendoim e cumpriu-se com os mais rigorosos crit?rios anal?ticos cromatogr?ficos estabelecidos pela UE. O m?todo apresentou uma corrida cromatogr?fica de 5 minutos e menor gasto de solventes org?nicos quando comparado ? t?cnica de HPLC. Os limites de detec??o alcan?ados foram de 1,6; 0,396; 1,608 e 1,396 ?g/kg ?g/kg?g/kg?g/kg para as AFB1, AFB2, AFG1 e AFG2, respectivamente, e foram obtidas curvas de calibra??o com boa linearidade entre os valores de 1,6 a 12,0 ?g/kg (AFB1 e AFG1) e 0,396 a 2,97 ?g/kg (AFB2 e AFG2). Foram analisadas 10 amostras de amendoim adquiridas em feira livre do Rio de Janeiro e identificados tra?os das aflatoxinas B1, B2 e G2 em duas delas

Dothistromin (DOTH) is a secondary metabolite produced by the fungal peanut pathogen Passalora arachidicola and pine needle pathogen Dothistroma septosporum. The chemical structure of DOTH is similar to a precursor of aflatoxin (AF) and sterigmatocystin (ST), which are secondary metabolites produced by Aspergillus species. A size fractionated genomic library was made and 11 putative DOTH genes were identified in P. arachidicola. The DOTH genes in P. arachidicola were compared to DOTH genes in D. septosporum as well as to AF and ST genes in Aspergillus species. The DOTH gene products in P. arachidicola showed 73 - 96% amino acid identity to DOTH genes in D. septosporum and 50 - 69% amino acid identity to AF/ST genes in Aspergillus. The DOTH biosynthesis genes in P. arachidicola had similar gene organization and direction of transcription to DOTH biosynthesis genes in D. septosporum and is similar in that 11 putative DOTH genes are separated into three mini-clusters. This differs from the AF/ST clusters in which 25 AF/ST genes are tightly clustered in a 70 kb region. Identification of transcription factor binding sites upstream of DOTH genes in P. arachidicola and D. septosporum suggested similar co-regulation of DOTH gene expression in P. arachidicola and D. septosporum. Tandem and inverted repeat sequences were identified in intergenic regions in the P. arachidicola DOTH gene cluster, but the distribution of those repeats appears to be random. This suggests that the fragmentation of the DOTH biosynthesis gene cluster is not due to retrotransposon activity or recombination between repeat sequences. The DOTH biosynthesis gene clusters in P. arachidicola and D. septosporum could be ancestral to AF/ST biosynthesis clusters in Aspergillus species.

Schätzungsweise 1 – 2 % der europäischen Bevölkerung reagieren allergisch auf bestimmte Lebensmittel. Die verantwortlichen Allergene sind meist Proteine und können während der Lebensmittelverarbeitung, vor allem infolge thermischer Prozesse, erheblich modifiziert werden. Daraus kann sowohl eine Senkung als auch eine Erhöhung des allergenen Potentials resultieren. Insbesondere die Entstehung von sog. „Neoepitopen“ in der Folge der Maillard-Reaktion ist bereits diskutiert worden. In der vorliegenden Arbeit wurde der Zusammenhang zwischen der Glykierung und dem allergenen Potential von Lebensmitteln, im Speziellen von Karotten und Erdnüssen, untersucht. Die Karottenallergie ist in der europäischen Bevölkerung relativ häufig. Etwa 23 – 25 % aller Nahrungsmittelallergiker leiden an dieser meist pollenassoziierten Allergie. Es ist bekannt, dass das allergene Potential von Karotten durch Hitzebehandlung, infolge der irreversiblen Denaturierung des Hauptallergens Dau c 1, stark gesenkt wird. Daher stellte sich die Frage, ob bestimmte Maillard-Reaktionsprodukte (MRP) als Indikatoren für die Senkung des allergenen Potentials infolge der Hitzebehandlung geeignet sind. Da zum Ausmaß der Maillard-Reaktion in hitzebehandelten Karotten bisher kaum Daten vorlagen, wurden zunächst Untersuchungen zu relevanten Glykierungsprodukten und zur resultierenden Aminosäuremodifizierung durchgeführt. In verschiedenen Handelsproben (Säfte, Breie, Konserven und getrocknete Karotten) waren neben Fru-Lys die Amadori-Produkte (AP) zahlreicher Aminosäuren, wie Fru-Ala und Fru-GABA nachweisbar. Als Produkte der fortgeschrittenen Phase der Maillard-Reaktion (advanced glycation endproducts, AGEs) wurden erstmals Pyrralin, Carboxymethyllysin (CML) und Pentosidin detektiert. Die resultierenden Aminosäure-modifizierungen waren in Produkten mit hohem Wasseranteil (Säfte, Breie sowie Konserven) mit bis zu 5 % gering. Dagegen zeigten getrocknete Karotten sehr hohe Derivatisierungsgrade (z. B. Lysin bis 58 %). Dabei war besonders die frühe Phase der Glykierung von Bedeutung, während die fortgeschrittene Phase kaum eine Rolle spielte. Das AP Fru-Lys bzw. dessen Hydrolyseprodukt Furosin gilt zwar als anerkannter Erhitzungsmarker für Lebensmittel, erwies sich aber in Karottenprodukten aufgrund von schnell stagnierenden Gehalten nur als bedingt geeignet. Insbesondere FM-GABA zeigte eine wesentlich bessere Korrelation mit der Intensität der Hitzebehandlung. Zudem korrelierte der Anstieg dieses AP gut mit der Senkung des Gehaltes an IgE-reaktivem Dau c 1. Damit ist FM-GABA ein geeigneter Parameter sowohl für die Hitzebehandlung von Karotten als auch für die damit verbundene Senkung des allergenen Potentials. Die Erdnussallergie gewinnt mit dem ansteigenden Verzehr von Erdnüssen zunehmend an Bedeutung. Diese Allergie zeichnet sich durch eine mitunter sehr schwere Symptomatik aus, so dass Erdnüsse hinsichtlich lebensbedrohender und letal verlaufender Nahrungsmittel-allergien an erster Stelle stehen. Bereits der Verzehr kleinster Mengen an Erdnuss, selbst Hautkontakt oder Inhalation können eine allergische Reaktion auslösen. Die Hauptallergene der Erdnuss, Ara h 1 und Ara h 2, sind bekanntermaßen stabil und behalten ihr allergenes Potential während der Hitzebehandlung bei. Dennoch besteht die Vermutung, dass die Zubereitung von Erdnüssen deren Allergenität maßgeblich beeinflusst. Daher wurde der Einfluss des Röstens bereits untersucht, jedoch sind die erhaltenen Ergebnisse bisher sehr widersprüchlich. Während in einigen Studien keine Unterschiede zwischen rohen und gerösteten Erdnüssen beobachtet wurden, berichteten andere Autoren von einer 90-fachen Erhöhung des IgE-Bindungsvermögens infolge der Röstung, die mit der Bildung von Neoepitopen durch die Maillard-Reaktion in Verbindung gebracht wurde. Aus diesem Grund wurde in der vorliegenden Arbeit der Einfluss der Röstung und insbesondere der Glykierung auf das allergene Potential von Erdnüssen untersucht. Da bisher kaum Daten zu MRP-Gehalten in Erdnüssen vorlagen, wurden zunächst verschiedene handelsübliche Proben (ungeröstete und geröstete Erdnüsse, Erdnussbutter und Erdnussflips) auf ihre Gehalte an Glykierungsprodukten und die resultierende Aminosäure-modifizierung untersucht. Dabei wurde erstmals das AP Fru-Lys und die AGEs Pyrralin und CML identifiziert und quantifiziert. Definierte Erhitzungsexperimente zeigten, dass während der Röstung von Erdnüssen insbesondere Pyrralin in hohen Mengen gebildet wird. Während in erhitzten Lebensmitteln üblicherweise Fru-Lys das dominierende MRP darstellt, trug Pyrralin in gerösteten Erdnüssen in vergleichbarem oder höherem Maße zur Lysinmodifizierung bei als das AP. Aufgrund der stetigen Zunahme ist Pyrralin als Erhitzungsparameter in Erdnüssen wesentlich besser geeignet als das Hydrolyseprodukt Furosin, dessen Gehalt schnell ein Plateau erreichte. Durch die Röstung von Erdnüssen wurden hohe Lysinmodifizierungen bis zu 55 % erreicht, die jedoch nur zu einem Zehntel durch die gemessenen MRP erklärbar waren. Da zahlreiche andere Aminosäuren ebenfalls deutliche Abnahmen zeigten, müssen andere Reaktionen neben der Maillard-Reaktion einen wesentlichen Beitrag zur Aminosäurederivatisierung leisten. Aufgrund des hohen Gehaltes an ungesättigten Fettsäuren liegt die Vermutung nahe, dass es sich um Reaktionen mit Lipidperoxidationsprodukten handeln könnte. Der Einfluss der Röstung auf das allergene Potential der Erdnüsse wurde anhand des Antikörperbindungsvermögens bewertet. Dabei zeigten die Proteinextrakte roher und gerösteter Erdnüsse keine Unterschiede in der IgE-Reaktivität. Jedoch sind aufgrund der schlechten Extrahierbarkeit gerösteter Erdnussproteine keine Rückschlüsse auf das allergene Potential der gesamten Erdnüsse möglich. Vor allem das Allergen Ara h 1 bildete zunächst Di- und Trimere, unter drastischeren Bedingungen kam es zur weiteren Aggregation und damit zur Unlöslichkeit. Analog wurde auch die Löslichkeit aller anderen Erdnussproteine deutlich reduziert. Folglich konnten insbesondere stark modifizierte, aggregierte Proteine mit der verwendeten Extraktionsmethode nicht erfasst werden. Mittels Immunoblot wurde gezeigt, dass das IgE-Bindungsvermögen des Ara h 1 bei der Röstung nicht verändert wurde, solange das Allergen noch löslich war. Aussagen zum allergenen Potential des aggregierten Proteins waren noch nicht möglich. Hingegen wurden deutliche Hinweise auf die Erhöhung der IgE-Reaktivität des Ara h 2 infolge der Röstung erhalten. Um den Einfluss der Maillard-Reaktion im Einzelnen auf die beiden Hauptallergene der Erdnuss, Ara h 1 und Ara h 2, untersuchen zu können, wurden diese Allergene aus rohen Erdnüssen isoliert und unter röstungsrelevanten Bedingungen glykiert. Durch diese Modifizierung wurde deren Antikörperbindungsvermögen jedoch nicht beeinflusst. Folglich liegen keine Hinweise auf die Bildung von Neoepitopen im Zuge der Maillard-Reaktion vor. Die beobachtete Erhöhung der IgE-Reaktivität des Ara h 2 infolge der Röstung ist daher auf andere Reaktionen, vermutlich mit Produkten der Lipidperoxidation, zurückzuführen. Die Grundvoraussetzung für eine allergische Reaktion ist, dass die verantwortlichen Epitope die gastrointestinale Verdauung überstehen und intakt aufgenommen werden. Durch thermische Behandlung und die daraus resultierende Umfaltung sowie kovalente Modifizierung kann die Verdauungsresistenz erheblich beeinflusst werden. Daher wurde mit Hilfe einer simulierten gastrointestinalen Verdauung der Einfluss der Röstung von Erdnüssen sowie der Glykierung von Ara h 1 und Ara h 2 auf die Verdaubarkeit der Allergene untersucht. Diese orientierenden Verdauungsstudien gaben Hinweise auf eine erhöhte Verdauungsresistenz der Proteinaggregate in gerösteten Erdnüssen. Durch Glykierung der Allergene Ara h 1 und Ara h 2 wurde hingegen keine Veränderung der Verdaubarkeit erreicht. Für die hohe Proteolyseresistenz der Proteine in gerösteten Erdnüssen sind offenbar wiederum Reaktionen mit peroxidierten Erdnusslipiden verantwortlich.

This thesis work aims the ionic liquid pretreatment of peanut shells for co-production of glucose as fermentable sugar and lignin, considering a multi product perspective. The effects of ionic liquid type and pretreatment time period on the sugar and lignin yields were investigated, as the particle size and temperature parameters were determined in the preliminary studies. Peanut shells were pretreated at constant temperature, 150 oC, for 5, 15 and 30 minutes with 1-ethyl-3-methylimidazolium acetate and for 15, 30 and 60 minutes with 1-ethyl-3-methylimidazolium chloride. The pretreated peanut shells were then subjected to enzymatic hydrolysis in order to produce fermentable sugars, mostly, glucose. The solid residue obtained upon enzymatic hydrolysis was analyzed in terms of lignin quantity. 1-ethyl-3-methylimidazolium acetate pretreatment for 15 minutes resulted in the maximum reducing sugar and lignin yields / 28 g of reducing sugar and 20 g of solid residue with 70% lignin were obtained per 100 g of peanut shells. Higher pretreatment time resulted in lower yields. Moreover, no optimal time period for 1-ethyl-3- methylimidazolium chloride pretreatment was obtained, since reducing sugar and lignin yields increased as the time period increased. Also all reducing sugar and lignin yields were lower than that obtained with 1-ethyl-3-methylimidazolium acetate. Lignin obtained upon enzymatic hydrolysis of 1-ethyl-3-methylimidazolium acetate pretreated peanut shells were characterized by SEM, FTIR, TGA and XRD analyses, which also showed the morphological and structural effects of pretreatment and enzymatic hydrolysis on peanut shells / and used as concrete admixture, which increased the flow of the concrete by 6%.

Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008. / Full text also available online. Scroll down for electronic link.