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Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2019.tde-20191218-161408
Document
Author
Full name
Rosângela Grisotto
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1992
Supervisor
Title in Portuguese
Construção e testes de câmara para tratamento térmico de esporos de microrganismos
Keywords in Portuguese
ESPOROS
MICRORGANISMOS
TRATAMENTO TÉRMICO
Abstract in Portuguese
O presente trabalho teve como objetivo apresentar planos de construcao de uma nova câmara de tratamento térmico de esporos de microrganismos, mais funcional e mais econômica que a utilizada em equipamento piloto anteriormente proposto (PRADO FILHO, 1987), bem como os resultados dos testes de funcionamento do modelo proposto e do tratamento térmico de esporos de Bacillus subitilis var niger ATCC 9372 com vapor super aquecido à temperaturas de 12s°C 137°C, 142°C e 150°C que correspondem a atividades de água medidas de 0,40; 0,30; 0,25 e 0,20 respectivamente, nas condições ambientais dos experimentos. O equipamento constituiu-se basicamente de um gerador de vapor de uma secção tubular de aquecimento e da nova câmara de tratamento de esporos. Os testes de funcionamento realizados demonstraram que a nova câmara garantiu muito boa estabilidade de temperatura dos experimentos. Com exceção de 137°C (Aa = 0,30), nas demais temperaturas o tratamento dos esporos evidenciou a ocorrência de fenômenos de ativação e inativação simultâneos ou sequenciais e, a presença de esporos muito mais resistentes que a média da populacao tratada. A 128°C e Aa = 0,40 o valor D da fração mais resistente da população de esporos tratada foi 195,31 minutos.
Title in English
Construction and tests of a microrganism spore thermal treatment chamber
Abstract in English
The present work had the objetive of presenting: a) construction plans of a new chamber for microrganism spore thermal treatment, being more functional and more economical than the one employed in a pilot equipment previously proposed (PRADO FILHO, 1987); and b) the proposed model working results and Bacillus subtilis var. niger ATCC 9372 spore thermal treatment data with superheated steam at temperatures 128°C, 137°C, 142°C and 150°C that correspond to measured water activities of 0,40; 0,30; 0,25 and 0,20, respectively, under experimental environmental conditions. Basically, the equipment consisted in a steam generator, a heating tubular section and the new spore treatment chamber. The working tests showed that the new chamber guaranteed a very good temperature stability in the experiments. Except for 137°C (Aw = 0,30), the spore treatment showed occurrence of simultaneous or sequentíal activation and inactivation phenomena and the presence of spores that were more resistant than the treated population's average. At 128°C and Aw = 0,40, the most resistant treated spore population fraction presented D value of 195,31 min.
 
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GrisottoRosangela.pdf (2.24 Mbytes)
Publishing Date
2019-12-19
 
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