UFV - Dissertações

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/3

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1972 - 197911990 - 19991

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Data inicial: 1970Tem arquivos: Não

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Agora exibindo 1 - 2 de 2
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    Detecção de microrganismos endofíticos em frutos de café
    (Universidade Federal de Viçosa, 1999) Yamada, Cecilia Mioko; Silva, Daison Olzany; Universidade Federal de Viçosa
    A presença e a distribuição de bactérias e leveduras em frutos de café, desinfestados superficialmente, foram observadas, utilizando-se técnicas de microscopia com colorações biológicas e fluorocromo, inclusão em parafina e técnicas imunológicas. As preparações a fresco e de inclusão em parafina possibilitaram observar a existência de um gradiente de distribuição de bactérias e leveduras na polpa do café, com predomínio de leveduras em sua porção mais externa. Foram encontradas, também, bactérias nas sementes de café. A aplicação de fluoresceína diacetato, em cortes a fresco, não se mostrou eficiente, dada a dificuldade de visualização dos microrganismos in situ e a inespecifidade da reação. Os anticorpos específicos, para a bactéria Klebsiella oxytoca, foram obtidos; porém, a aplicação de imunofluorescência usando anticorpos como sonda, para detecção das bactérias, em tecidos de frutos de café, necessita de adaptações.
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    Fatores de armazenagem que afetam a qualidade do café
    (Purdue University, 1972) Hara, Tetuo; Zachariah, G. L.; Purdue University
    The United States imports more than 20 million bags of coffee beans annually corresponding to a value of more than one billion dollars, mainly through the ports of New York, New Orleans, and San Francisco. They are normally stored for a period of time depending on the schedule for further distribution to roaster plants or re-exported. Therefore they are subjected to varying warehouse environmental conditions including temperature, humidity, light exposure, and darkness. Coffee quality is also related to its color. The mentioned storage factors may cause color change on coffee beans during the storage period. Four commercial Arabica coffee from Hawaii, Brazil, Colombia, and Mexico were chosen for the study. Color evaluation of coffee beans was made by visual observation and by spectrophotometer. The relative reflectance was measured over a number of beans covering an area equivalent to a circle with approximately 2 inches in diameter. A supplementary test was conducted by measuring the relative reflectance of individual coffee beans. After two weeks of treatmnents the color of the coffee beans was evaluated and data were compared with those at initial conditions. Results indicated that at low temperature, and with exposure to light the color of the coffee beans was practically unchanged. In some cases an apparent improvement in color quality was observed. All samples stored in the dark showed bleached beans and all those exposed to constant Iight maintained their initial color in most of the cases. High temperature tended to darken the green color and an overall darker color. The spectrophotometric readings did not provide sufficient information to detect obvious bleached beans in some cases.