Application of the acid hydrolysis of sucrose as a temperature indicator in continuous thermal processes

Detalhes bibliográficos
Autor(a) principal: Torres, A. Pinheiro
Data de Publicação: 1999
Outros Autores: Oliveira, F. A. R.
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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spelling 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
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection 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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