Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2001. / Härtill 6 uppsatser.

Halle, Universiẗat, Diss., 1999.

Frankfurt (Main), Universiẗat, Diss., 2001.

No description available.

No description available.

Orientador: Marcos David Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-07T02:04:39Z (GMT). No. of bitstreams: 1 Ferrari_PauloRoberto_M.pdf: 2682736 bytes, checksum: 1234e4cfee02d4d64bcd7f8c5707982f (MD5) Previous issue date: 2005 / Resumo: A tomaticultura de mesa nos últimos seis anos evoluiu com a implantação de unidades de beneficiamento, classificando os tomates através de equipamentos com sistema eletrônico e mecânico de classificação. A avaliação da classificação foi desenvolvida em duas unidades de beneficiamento de tomates de mesa, sistema de classificação eletrônica e mecânica, e em dois períodos de produção, safras de verão e inverno. O cultivar utilizado foi Carmen. Para cada safra foram realizadas três etapas: (1) Avaliar a conformidade de classificação por diâmetro e coloração dos equipamentos com sistema eletrônico e mecânico de classificação com o PROGRAMA BRASILEIRO PARA A MODERNIZAÇÃO DA HORTICULTURA (2003), (2) Verificar a conformidade de classificação por diâmetro obtida dos equipamentos, com a regulagem programada pela unidade de beneficiamento e (3) Acompanhamento da vida pós-colheita dos tomates provenientes da classificação nesses equipamentos em laboratório da Faculdade de Engenharia Agrícola ¿ UNICAMP, onde os tomates ficaram armazenados em câmara de refrigeração a temperatura ambiente de 24 ± 1ºC e umidade relativa de 75 ± 5% por um período de 20 dias. Foram realizadas análises como, perda de massa, qualidade visual, evolução da coloração, firmeza e químicas (pH, sólido solúvel, acidez titulável) e cálculo da relação sólido solúvel/acidez titulável. Dentre os resultados, não houve conformidade de classificação por diâmetro e coloração, dos equipamentos, com a norma de classificação do Programa. A conformidade de classificação obtida com a programada apresentou somente para classe de maior diâmetro, em ambos os equipamentos. Na avaliação da qualidade visual, os frutos sadios após armazenamento por 20 dias não apresentaram diferença significativa entre os equipamentos. Como razão de descarte, na safra de verão, enrugamento foi mais freqüente no equipamento eletrônico e a podridão no mecânico, na safra de inverno os descartes foram mais freqüentes no equipamento mecânico. A perda de massa foi maior no equipamento mecânico em ambas as safras. A evolução da coloração dos tomates foi mais intensa na safra de verão no equipamento mecânico e menor intensidade no inverno para o mesmo equipamento. Não houve diferenças significativas para a variação do índice de firmeza entre os equipamentos. As análises das características químicas, não foram significativas. O equipamento eletrônico apresentou melhor desempenho sobre o equipamento mecânico, em relação à classificação e na qualidade da vida pós-colheita dos frutos provenientes desta classificação. Embora utilize alta tecnologia, este equipamento deverá ser monitorado constantemente em suas atividades visando sua eficiência e viabilização do seu investimento. Pelos resultados apresentados, recomenda-se para o sistema mecânico, rever o sistema de classificação de correia de lona furada para que atenda a legislação de classificação do Programa Brasileiro para a Modernização da Horticultura, e garanta melhor desempenho nas etapas de lavagem, secagem e polimento / Abstract: The fresh market tomato industry has been evolved, in the last six years, with the implantation of tomato grade machines, electronical and mechanical equipments. Evaluation of the grading performance electronical and mechanical equipments was done at summer and winter seasons. The cultivar studied was Carmen. For each season, three main points were studied: (1) Evolution of the size and color grading conformity with the BRAZILIAN PROGRAM FOR HORTICULTURE MODERNIZATION standards. (2) Evaluation of size grading conformity with the one established by the packer. (3) Post harvest shelf life and grading quality of tomatoes during for 20 days in controlled environment at 24ºC ± 1ºC and 75% ± 5% RH, FEAGRI/UNICAMP. During storage, visual quality evaluation and physical and physical chemical analysis were done: weight loss, color evolution, firmness, pH, soluble solids, tritratable acidity and ratio. There was no grade conformity with the fresh tomato quality standards of the BRAZILIAN PROGRAM FOR HORTICULTURE MODERNIZATION. There was conformity with the grading programmed by the packer, only for large size, in both equipments. After storage for 20 days, there were not any significant statistic difference on fruit quality sorted by electronical and mechanical equipments. For summer season, the major cause for fruit discharge was shrunken fruits in electronical equipment and decay in mechanical equipment. For winter season there were high post harvest losses at the mechanical equipment. The highest weight loss was found on fruits sorted at the mechanical equipment at the two seasons. The mechanical equipment showed the most intense color evolution at summer season and the less intense at winter season. There were not statistical differences between the equipments for firmness loss. There were also not statistical differences, between the equipments for chemical analyses. The electronical equipment has presented better performance, compared to the mechanical equipment, considering grading performance and post-harvest fruits quality. Despite of its high technology the electronical equipment must be constantly monitored to achieve efficiency and return of the investment. The mechanical system must review its size grading, to achieve grade standards stablished by the BRAZILIAN PROGRAM FOR HORTICULTURE MODERNIZATION and must improve its cleaning operation / Mestrado / Tecnologia Pós-Colheita / Mestre em Engenharia Agrícola

Memoria para optar al Título Profesional de Químico y al Grado de Magíster en Química, área de especialización en coloides / El metabolismo celular es un proceso natural en los organismos vivos que conduce inevitablemente a la producción de especies reactivas del oxígeno, conocidas como ROS, las cuales, son agentes oxidantes altamente reactivos capaces de atacar células, causando en ellas la pérdida de su estructura y funciones. El exceso de ROS en el organismo, un estado que se conoce como “estrés oxidativo”, es mantenido bajo control por mecanismos celulares y especies antioxidantes, evitando que se desencadenen enfermedades relacionadas con la oxidación celular. Entre las ROS se encuentra el oxígeno molecular singulete, O2(a¹Δg), especie que es capaz de reaccionar con gran variedad de moléculas biológicas, tales como el ADN, proteínas y lípidos, desempeñando roles perjudiciales y/o beneficiosos en el organismo. El O2(a¹Δg) es uno de los dos posibles estados excitados del oxígeno, pero es el único que tiene un tiempo de vida los suficientemente largo para ser relevante en las reacciones químicas en solución. Se puede generar por vía química, física o fotoquímica, siendo esta última la más utilizada por ser la más simple y controlable. La cinética de sus reacciones con sustratos, o desactivantes (Q), puede ser descrita en términos de la constante de velocidad de desactivación total, que incluye las vías de reacción química y física. El método ideal para evaluar, es la detección directa de la emisión fosforescente del O2(a¹Δg) en el infrarrojo cercano, utilizando la fotosensibilización como método de generación de O2(a¹Δg). Sin embargo, esta técnica tiene serias limitaciones debido a la sensibilidad de los detectores y la complejidad del proceso de decaimiento del O2(a¹Δg) en sistemas de interés biológico, cuya microheterogeneidad, hace que ocurran gradientes en la concentración local del O2(a¹Δg) afectando su reactividad, situación que puede ser parcialmente imitada en sistemas bien definidos, tales como soluciones de micelas y liposomas. El modelo más apto para entender las reacciones del O2(a¹Δg) en sistemas biológicos lo constituyen las vesículas unilamelares, las cuales, se componen de una única bicapa bien definida que permite distinguir en ellas dos pseudofases, una acuosa y otra lipídica. El modelamiento cinético en estos sistemas es una tarea compleja, pero cercana a lo que sucede a nivel celular. Como alternativa a la detección directa del O2(a¹Δg)en sistemas biológicos, en nuestro laboratorio se han sintetizado los derivados de furano; DFTA, HFDA y MFMA, que además de reaccionar eficientemente con O2(a¹Δg)a través de la vía química, pueden anclarse en la membrana desde la interfase, permitiendo estudiar la dinámica del oxígeno singulete y estimar su concentración estacionaria a distintas profundidades en la bicapa. Esta información, sumada a estudios teóricos relacionados con el transporte de moléculas pequeñas a través de la membrana lipídica, permiten obtener una aproximación cuantitativa de la distribución del O2(a¹Δg) en ella. En este trabajo se estudia, en soluciones de vesículas unilamelares de DODAC y de DPPC, la interacción del O2(a¹Δg) con los sustratos licopeno, ácido rosmarínico y ácido carnósico, en forma independiente. Los tres sustratos poseen un origen natural y conocida capacidad antioxidante. En el experimento, el O2(a¹Δg)es generado por fotosensibilización, mientras que las soluciones de vesículas, con los derivados de furano y los antioxidantes incorporados en la bicapa, son generadas por el método de inyección… / Cellular metabolism is a natural process in living organisms that inevitably leads to the production of reactive oxygen species, known as ROS, which are highly reactive oxidizing agents capable of attacking cells, causing the loss of their structure and functions. The excess of ROS in the body, a condition known as “oxidative stress” is kept under control by cellular mechanisms and antioxidant species, avoiding the triggering of diseases related to cell oxidation. Among the ROS, singlet molecular oxygen O2(a¹Δg) is a specie capable of reacting with a variety of biological molecules, such as DNA, proteins and lipids, playing harmful and/or beneficial roles in the body. O2(a¹Δg) is one of the two possible excited states of the oxygen, but is the only one with a lifetime long enough for relevant chemical reactions in solution. It can be generated in a chemical, physical and photochemical way, the last being the most used method, being the simplest and most controllable. The kinetics of its reactions with other substrates, or quenchers, may be described in terms of the total deactivation rate constant including pathways for chemical and physical reactions. The ideal method to evaluate is the detection of the phosphorescence in the near-infrared, usually using photosensitization as a generating method for O2(a¹Δg). However, this technique has serious limitations due to the sensitivity of detectors and the complexity of the decay process in systems of biological interest, where the microheterogeneity, characteristic of biological systems, makes gradients occur in the local concentration and reactivity of O2(a¹Δg), a situation that can be partly replicated in well-defined systems such as micelles and liposomes solutions. The most suitable model to understand the reactions of O2(a¹Δg) in biological systems are unilamellar vesicles, which are composed of a single bilayer well defined to distinguish two pseudofases therein, aqueous and lipidic. The kinetic modeling of these systems is complex, but close to what happens at the cellular level. As an alternative to direct detection of O2(a¹Δg) in biological systems, several derivate of furan (DFTA, HFDA and MFMA) have been synthesized in our laboratory, which in addition to react efficiently with O2(a¹Δg) through chemicals pathways, they can be anchored to the membrane from the interface, allowing to study the dynamics of singlet oxygen and estimate their stationary concentration at different depths inside the bilayer. This information, together with theoretical studies related to the transport of small molecules through the lipid membrane allows obtaining a quantitative approach about the distribution of O2(a¹Δg) in the bilayer. In this work, a study concerning the interaction of O2(a¹Δg) with the substrates lycopene, rosmarinic acid and carnosic acid, in solutions of unilamellar vesicles of DODAC and DPPC, is presented. The three substrates possess a natural origin and a known antioxidant capability. In the experiment O2(a¹Δg) is generated by photosensitization, while solutions of vesicles, with the furan derivatives and antioxidants incorporated in the bilayer, are generated by the injection method. HFDA is the furan derivative that places the reactive group deeper into the bilayer, and thus, the one that probes more information regarding to the O2(a¹Δg) inside, is obtained for the three antioxidants through a kinetic model of two pseudofases, previously developed in our laboratory, where molecules of antioxidants and HFDA competing for reaction with O2(a¹Δg). The values of ,are also obtained by time-resolved methods, in order to make a comparison between them and obtained through the salts of furan by the method of the competitive reactions. The values of obtained for lycopene are close to those obtained by other authors in similar conditions. On the other hand, for rosmarinic and carnosic acids do not exist previous studies specifically related to O2(a¹Δg), however, the high value of the obtained for these substrates indicates that they play a significant protective effect against damage caused by O2(a¹Δg) in lipidic membranes, finding values in one order of magnitude higher than to those determined in methanol. / Conicyt, Fondecyt

Memori a para optar al Titulo Profesional de Ingeniero Agrónomo Mención: Fitotecnia / La presente investigación se realizó con el objeto de evaluar 22 cultivares de tomate industrial para pasta, desde el punto de vista de la caracterización de su etapa productiva y de la calidad de sus frutos como materia prima. Esto debido a que hoy en día son varios los cultivares de tomate industrial que han sido introducidos en el país, y anualmente aparecen otros con nuevas características para satisfacer los requerimientos de los productores y de los consumidores. Así la elección del cultivar debe ser lo más cuidadoso posible ya que la materia prima para industrialización debe tener características especiales.

Recent reports, especially those of Russian scientists, have emphasized that application of stimulatory concentrations of naphthenates (Naps) induced greater and better growth and productivity of a number of species of plants. This stimulatory action of Naps has been found to result from seed soaking and spraying seeds or developing plants once or repeatedly. However, no systematic attempt has so far been made to investigate physiological and biochemical changes induced in a relative short period following immediately these treatments. A correlation of such changes with final improvements in growth and yield may provide a better understanding of the mechanism of action of Naps It was therefore essential and significant to investigate these aspects. Seeds of tomato (Lycopersicum esculentum var. Bonny Best) were germinated in wooden flats containing sterilized soil and were transplanted when 10 days old to plastic pots of 6 inche diameter containing sterilized soil. The plants were grown in a growth room. In separate experiments, potassium naphthenate (KNap) aqueous solutions, 2,500 ppm and 5,000 ppm, were sprayed onto tomato leaves when plants were 2, 3, and 4 weeks old. Measurements of vegetative growth, based on fresh and dry weights of plant tops, indicated that maximum stimulation was induced by the 5,000 ppm KNap solution applied to plants when 3 weeks old. It was then decided to investigate the biochemical and physiological responses of the tomato plants to 5,000 ppm KNap when treated at the age of 3 weeks. Determinations of pigment content, intensities of photosynthesis and respiration, activity of enzymes involved in nitrogen metabolism, such as nitrate reductase (NRase) and glutamic-pyruvic transaminase (transaminase), and of enzymes involved in carbohydrate metabolism, such as succinic dehydrogenase, phosphorylase, and phosphoglyceryl kinase were made three times at 2-week intervals, beginning 2 weeks after the spraying. Number and fresh weight of tomato fruits, quality of tomato fruits in terms of sugars, titratable acidity and ascorbic acid were also investigated at scheduled intervals. Results indicated the following: (1) In the treated plants, the content of the pigments chlorophyll a and b, and especially carotenoid, in the leaf blades was higher than in control plants, (2) Measurements made with intact plants using an infrared CO₂ analyzer revealed increases in intensities of photosynthesis and respiration of the aerial portions 4 weeks after treatment but the opposite was true 2 weeks after treatment, (3) Under the influence of KNap, of the 5 enzymes examined only phosphorylase activity was found to be stimulated at all three observation times. Transaminase activity was greater 6 weeks after treatment. Activities of succinic dehydrogenase, NRase, and phosphoglyceryl kinase were all reduced by treatments, (4) In a subsequent experiment, leaf blades of plants treated when 2 weeks old were analyzed for succinic dehydrogenase activity 4, 8, 12, 16, 20, and 24 days after spraying. The effect on succinic dehydrogenase activity fluctuated with the age of the plant. Parallel changes in the protein content of the enzyme extract could not be detected, (5) Tomato fruit yield, based on number and fresh weight, was decreased by 2,500 ppm KNap treatment but increased by 5,000 ppm KNap. In addition, 5,000 ppm KNap-treated plants were more resistant to blossom-end rot and showed better and quicker recovery when the deficiency disease was treated with CaCl₂. Earlier maturity was found in 5,000 ppm KNap-treated plants, (6) The mature tomato fruits from 5,000 ppm KNap-treated plants contained larger amounts of sugars (reducing sugar and sucrose) than the controls, and the sugars in mature tomato fruits were lost at a lower rate during the storage period. The treatment resulted in decreased titratable acid and ascorbic acid content. It afforded no protection against loss of titratable acid and ascorbic acid during storage. / Science, Faculty of / Botany, Department of / Graduate

No description available.