Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes
Autor(a) principal: | |
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Data de Publicação: | 1999 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.14/6799 |
Resumo: | The hydrolysis of sucrose in an acid medium was used as a temperature indicator to measure holding temperatures in a continuous thermal-processing unit. From a theoretical analysis, target conversion (χ) and errors in both acid concentration and conversion measurements were found to affect significantly the accuracy of predicted temperatures, whereas errors in the determination of the fluid mean residence time did not show a significant effect. For different pasteurisation temperatures (70°C < T < 86°C) and flow rates (4800< Re< 11,300), the acid concentration in the medium was adjusted so that different extents of reaction could be tested, as the reaction rate was found to increase exponentially with [H+]. Nitric acid solutions were circulated through the unit, a sucrose solution was continuously fed to the entrance of the holding tube and sucrose concentration was analysed at the half way part and at the exit of the holding tube. The temperature of the holding section was then estimated from the measured conversion. These results compared well with thermocouple measurements, with deviations of less than 4°C for conversions between 0.4 and 0.7, whereas greater errors were obtained for both low and high conversions. |
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Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processesHoldingPasteurisationTemperature AssessmentTime-temperature indicatorThe hydrolysis of sucrose in an acid medium was used as a temperature indicator to measure holding temperatures in a continuous thermal-processing unit. From a theoretical analysis, target conversion (χ) and errors in both acid concentration and conversion measurements were found to affect significantly the accuracy of predicted temperatures, whereas errors in the determination of the fluid mean residence time did not show a significant effect. For different pasteurisation temperatures (70°C < T < 86°C) and flow rates (4800< Re< 11,300), the acid concentration in the medium was adjusted so that different extents of reaction could be tested, as the reaction rate was found to increase exponentially with [H+]. Nitric acid solutions were circulated through the unit, a sucrose solution was continuously fed to the entrance of the holding tube and sucrose concentration was analysed at the half way part and at the exit of the holding tube. The temperature of the holding section was then estimated from the measured conversion. These results compared well with thermocouple measurements, with deviations of less than 4°C for conversions between 0.4 and 0.7, whereas greater errors were obtained for both low and high conversions.ElsevierVeritati - Repositório Institucional da Universidade Católica PortuguesaTorres, A. PinheiroOliveira, F. A. R.2011-10-22T11:44:59Z19991999-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.14/6799engTORRES, A. Pinheiro ; OLIVEIRA, F.A.R. - Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes. Journal of Food Engineering. ISSN 0260-8774. Vol. 40, n.º 3 (1999), p. 181-18810.1016/S0260-8774(99)00054-0info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-12T17:10:41Zoai:repositorio.ucp.pt:10400.14/6799Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T18:05:53.990180Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
title |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
spellingShingle |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes Torres, A. Pinheiro Holding Pasteurisation Temperature Assessment Time-temperature indicator |
title_short |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
title_full |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
title_fullStr |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
title_full_unstemmed |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
title_sort |
Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes |
author |
Torres, A. Pinheiro |
author_facet |
Torres, A. Pinheiro Oliveira, F. A. R. |
author_role |
author |
author2 |
Oliveira, F. A. R. |
author2_role |
author |
dc.contributor.none.fl_str_mv |
Veritati - Repositório Institucional da Universidade Católica Portuguesa |
dc.contributor.author.fl_str_mv |
Torres, A. Pinheiro Oliveira, F. A. R. |
dc.subject.por.fl_str_mv |
Holding Pasteurisation Temperature Assessment Time-temperature indicator |
topic |
Holding Pasteurisation Temperature Assessment Time-temperature indicator |
description |
The hydrolysis of sucrose in an acid medium was used as a temperature indicator to measure holding temperatures in a continuous thermal-processing unit. From a theoretical analysis, target conversion (χ) and errors in both acid concentration and conversion measurements were found to affect significantly the accuracy of predicted temperatures, whereas errors in the determination of the fluid mean residence time did not show a significant effect. For different pasteurisation temperatures (70°C < T < 86°C) and flow rates (4800< Re< 11,300), the acid concentration in the medium was adjusted so that different extents of reaction could be tested, as the reaction rate was found to increase exponentially with [H+]. Nitric acid solutions were circulated through the unit, a sucrose solution was continuously fed to the entrance of the holding tube and sucrose concentration was analysed at the half way part and at the exit of the holding tube. The temperature of the holding section was then estimated from the measured conversion. These results compared well with thermocouple measurements, with deviations of less than 4°C for conversions between 0.4 and 0.7, whereas greater errors were obtained for both low and high conversions. |
publishDate |
1999 |
dc.date.none.fl_str_mv |
1999 1999-01-01T00:00:00Z 2011-10-22T11:44:59Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.14/6799 |
url |
http://hdl.handle.net/10400.14/6799 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
TORRES, A. Pinheiro ; OLIVEIRA, F.A.R. - Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes. Journal of Food Engineering. ISSN 0260-8774. Vol. 40, n.º 3 (1999), p. 181-188 10.1016/S0260-8774(99)00054-0 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier |
publisher.none.fl_str_mv |
Elsevier |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799131725385695232 |