Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais
Ano de defesa: | 2007 |
---|---|
Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de São Carlos
|
Programa de Pós-Graduação: |
Programa de Pós-Graduação em Química - PPGQ
|
Departamento: |
Não Informado pela instituição
|
País: |
BR
|
Palavras-chave em Português: | |
Área do conhecimento CNPq: | |
Link de acesso: | https://repositorio.ufscar.br/handle/ufscar/6121 |
Resumo: | Coffee is an important product of Brazilian agribusiness. Nevertheless, the commercial evaluation of its quality is based upon subjective methods and this requires the methodologies development that provides information on differences of coffee chemical composition of different traits. The current work describes the application of multivariate analysis methods, mainly in NMR data, in order to verify chemical differences related to certain attributes that determine the coffee quality. In this work, the specie used in the brew preparation, defective coffee beans, adulteration with barley, the effect of temperature and time on the roasted coffee composition, cup quality and production mode were studied. In the first study, it was determined the main differences between the composition of arabica and robusta coffee discriminating both species and was determined the content of each one in blends. In similar study, were discriminated blends of coffee and barley and was determined the percentage of this adulterant added to the coffee. In this case, comparing to NMR, the infrared spectroscopy also shows great efficiency for the same purpose. In the study of defective coffee beans were verified greater changes in the chemical composition of black beans compared to the non-defective coffee besides the discrimination of all kinds of defective beans analyzed; green, sour, and black. Considering the production mode, were discriminated coffees produced conventionally and organically. The higher acetic acid content in the organic samples was determinant to this discrimination. Considering the cup quality, efficient chemometric models were obtained to classify the samples with different qualities - soft, hard, and rio. The lipid compounds were important to this classification and were identified by using HR-MAS technique. In the study of roast degree it was verified greater influence of the temperature in the chemical composition changes from roasted coffees and it was possible to discriminate samples that were submitted to several conditions of time and temperature during roast process. |
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Tavares, Leila AleyFerreira, Antonio Gilbertohttp://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4721956Y6http://lattes.cnpq.br/95632624418002752016-06-02T20:34:12Z2009-09-252016-06-02T20:34:12Z2007-03-02TAVARES, Leila Aley. THE USE OF CHEMOMETRIC METHODS AND NMR IN THE CHARACTERIZATION OF DIFFERENT TYPES OF COMMERCIAL COFFEES. 2007. 194 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2007.https://repositorio.ufscar.br/handle/ufscar/6121Coffee is an important product of Brazilian agribusiness. Nevertheless, the commercial evaluation of its quality is based upon subjective methods and this requires the methodologies development that provides information on differences of coffee chemical composition of different traits. The current work describes the application of multivariate analysis methods, mainly in NMR data, in order to verify chemical differences related to certain attributes that determine the coffee quality. In this work, the specie used in the brew preparation, defective coffee beans, adulteration with barley, the effect of temperature and time on the roasted coffee composition, cup quality and production mode were studied. In the first study, it was determined the main differences between the composition of arabica and robusta coffee discriminating both species and was determined the content of each one in blends. In similar study, were discriminated blends of coffee and barley and was determined the percentage of this adulterant added to the coffee. In this case, comparing to NMR, the infrared spectroscopy also shows great efficiency for the same purpose. In the study of defective coffee beans were verified greater changes in the chemical composition of black beans compared to the non-defective coffee besides the discrimination of all kinds of defective beans analyzed; green, sour, and black. Considering the production mode, were discriminated coffees produced conventionally and organically. The higher acetic acid content in the organic samples was determinant to this discrimination. Considering the cup quality, efficient chemometric models were obtained to classify the samples with different qualities - soft, hard, and rio. The lipid compounds were important to this classification and were identified by using HR-MAS technique. In the study of roast degree it was verified greater influence of the temperature in the chemical composition changes from roasted coffees and it was possible to discriminate samples that were submitted to several conditions of time and temperature during roast process.O café é um importante produto do agronegócio brasileiro. Entretanto, a avaliação comercial da sua qualidade é feita por métodos subjetivos, tornando-se necessário o desenvolvimento de metodologias que sejam capazes de atuar no controle de qualidade e ao mesmo tempo fornecer informações a respeito das diferenças na composição química dos cafés com diferentes características. O presente trabalho descreve a aplicação de métodos de análise multivariada, principalmente, em dados de RMN de 1H com o objetivo de verificar as diferenças químicas relacionadas a certos atributos determinantes da qualidade do café. Nesse trabalho, foram estudados a espécie utilizada na preparação da bebida, grãos de café defeituosos, a adulteração com cevada, o efeito da temperatura e do tempo na composição dos cafés torrados, a classificação sensorial da bebida e o modo de produção. No primeiro estudo, determinou-se as principais diferenças na composição química das duas espécies de maior importância comercial, arábica e robusta, discriminando-as e determinando o teor delas em diferentes misturas. Em estudo semelhante, discriminou-se misturas de café contendo diferentes teores de cevada, além de determinar o teor adicionado ao café. Nesse caso, em comparação com a RMN, a espectroscopia de infravermelho mostrou eficiência similar para o mesmo propósito. No estudo dos cafés com defeitos, verificou-se uma maior alteração na composição química dos grãos com defeitos do tipo preto em relação ao café de boa qualidade, além da discriminação entre todos os tipos analisados; verdes, ardidos e pretos. Quanto ao modo de produção, cafés produzidos convencionalmente e organicamente foram discriminados entre si, sendo o maior teor de ácido acético nos cafés orgânicos a principal diferença apontada nas amostras estudadas. Quanto à classificação sensorial, foi possível construir modelos quimiométricos capazes de atribuir corretamente a qualidade de amostras com diferentes classificações na prova de xícara. Dentre os compostos responsáveis por essa classificação estão os lipídeos, os quais foram identificados com a utilização da técnica HR-MAS. Com relação ao grau de torra, além de verificar uma maior influência da temperatura na alteração da composição do café torrado, foi possível discriminar amostras torradas em diversas condições de tempo e temperatura.Financiadora de Estudos e Projetosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarBRQuímicaRessonância magnética nuclearQuimiometriaCaféControle de qualidadeCIENCIAS EXATAS E DA TERRA::QUIMICAUtilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciaisTHE USE OF CHEMOMETRIC METHODS AND NMR IN THE CHARACTERIZATION OF DIFFERENT TYPES OF COMMERCIAL COFFEESinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL2106.pdfapplication/pdf3096328https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/6121/1/2106.pdf1f871e02acc495485a1fbc5eb9dafc54MD51THUMBNAIL2106.pdf.jpg2106.pdf.jpgIM Thumbnailimage/jpeg10978https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/6121/2/2106.pdf.jpgdae46889ae8291d725616ecdd6d1ab32MD52ufscar/61212019-09-11 02:56:18.093oai:repositorio.ufscar.br:ufscar/6121Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-05-25T12:50:51.552752Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
dc.title.alternative.eng.fl_str_mv |
THE USE OF CHEMOMETRIC METHODS AND NMR IN THE CHARACTERIZATION OF DIFFERENT TYPES OF COMMERCIAL COFFEES |
title |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
spellingShingle |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais Tavares, Leila Aley Química Ressonância magnética nuclear Quimiometria Café Controle de qualidade CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
title_full |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
title_fullStr |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
title_full_unstemmed |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
title_sort |
Utilização de métodos quimiométricos aliados a RMN na caracterização dos diferentes tipos de cafés comerciais |
author |
Tavares, Leila Aley |
author_facet |
Tavares, Leila Aley |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/9563262441800275 |
dc.contributor.author.fl_str_mv |
Tavares, Leila Aley |
dc.contributor.advisor1.fl_str_mv |
Ferreira, Antonio Gilberto |
dc.contributor.advisor1Lattes.fl_str_mv |
http://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4721956Y6 |
contributor_str_mv |
Ferreira, Antonio Gilberto |
dc.subject.por.fl_str_mv |
Química Ressonância magnética nuclear Quimiometria Café Controle de qualidade |
topic |
Química Ressonância magnética nuclear Quimiometria Café Controle de qualidade CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
Coffee is an important product of Brazilian agribusiness. Nevertheless, the commercial evaluation of its quality is based upon subjective methods and this requires the methodologies development that provides information on differences of coffee chemical composition of different traits. The current work describes the application of multivariate analysis methods, mainly in NMR data, in order to verify chemical differences related to certain attributes that determine the coffee quality. In this work, the specie used in the brew preparation, defective coffee beans, adulteration with barley, the effect of temperature and time on the roasted coffee composition, cup quality and production mode were studied. In the first study, it was determined the main differences between the composition of arabica and robusta coffee discriminating both species and was determined the content of each one in blends. In similar study, were discriminated blends of coffee and barley and was determined the percentage of this adulterant added to the coffee. In this case, comparing to NMR, the infrared spectroscopy also shows great efficiency for the same purpose. In the study of defective coffee beans were verified greater changes in the chemical composition of black beans compared to the non-defective coffee besides the discrimination of all kinds of defective beans analyzed; green, sour, and black. Considering the production mode, were discriminated coffees produced conventionally and organically. The higher acetic acid content in the organic samples was determinant to this discrimination. Considering the cup quality, efficient chemometric models were obtained to classify the samples with different qualities - soft, hard, and rio. The lipid compounds were important to this classification and were identified by using HR-MAS technique. In the study of roast degree it was verified greater influence of the temperature in the chemical composition changes from roasted coffees and it was possible to discriminate samples that were submitted to several conditions of time and temperature during roast process. |
publishDate |
2007 |
dc.date.issued.fl_str_mv |
2007-03-02 |
dc.date.available.fl_str_mv |
2009-09-25 2016-06-02T20:34:12Z |
dc.date.accessioned.fl_str_mv |
2016-06-02T20:34:12Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
TAVARES, Leila Aley. THE USE OF CHEMOMETRIC METHODS AND NMR IN THE CHARACTERIZATION OF DIFFERENT TYPES OF COMMERCIAL COFFEES. 2007. 194 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2007. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/6121 |
identifier_str_mv |
TAVARES, Leila Aley. THE USE OF CHEMOMETRIC METHODS AND NMR IN THE CHARACTERIZATION OF DIFFERENT TYPES OF COMMERCIAL COFFEES. 2007. 194 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2007. |
url |
https://repositorio.ufscar.br/handle/ufscar/6121 |
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por |
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openAccess |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Química - PPGQ |
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UFSCar |
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BR |
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Universidade Federal de São Carlos |
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