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Abstract(s)
O vinho é uma mistura de composição química extremamente complexa, resultando da fermentação de uvas por leveduras nomeadamente Saccharomyces cerevisiae. A análise deste tipo de amostras é um dos maiores desafios da química analítica que tem impacto na qualidade de produção e na avaliação da autenticidade sendo que são usadas maioritariamente métodos analíticos convencionais (NMR, cromatográficos e hifenados) que são muito morosos e permitem identificar um reduzido número de compostos. A análise de amostras complexas de uma forma completa num curto espaço de tempo e o desenvolvimento e a implementação de metodologias analíticas que o possibilitem, é um dos objectivos promissores na química analítica dos dias de hoje e que levam à elevada procura de conhecimento e à descoberta de soluções. Os principais objectivos deste trabalho foram, em primeiro lugar, a análise e caracterização do perfil químico de vinhos monocastas utilizando uma técnica analítica muito precisa e eficaz para a caracterização de vinhos, a espectrometria de massa de ressonância ciclotrónica de ião com transformada de Fourier – FT-ICR-MS. O segundo, a quantificação de catequinas em vinhos monocastas e em folhas de videiras por cromatografia líquida de alta eficiência (HPLC) com dois detectores: fluorescência e matriz de díodos. Foram analisados vinhos monocastas de diferentes anos, brancos e tintos, fornecidos pelo Instituto Nacional de Investigação Agrária e Veterinária, I. P. – INIAV (Polo dois Portos). Estes vinhos foram produzidos sob condições controladas e diferentes anos de produção (2015-2018). As amostras de vinhos monocastas foram preparadas por diluição em MeOH. Cada amostra analisada continha padrão interno, Leucina Enkephalin. As amostras foram posteriormente analisadas por FT-ICR-MS por infusão directa por electrospray em modo positivo, sendo efectuados 3 replicados de cada amostra de vinho. Para as amostras de vinho branco o número de possíveis compostos determinados variou entre 1187 e 11882 e para as amostras de vinho tinto o número de compostos variou entre 1957 e 13591. Após a análise pelo DataAnalysis a lista de picos foi submetida ao portal MassTRIX por forma a identificar a presença de alguns compostos químicos nos vinhos monocastas. Pelo MassTRIX obtiveram-se um número de compostos na ordem das centenas. Foi observado que também o vinho verdelho 2018 (777 compostos) e o vinho verdelho tinto 2015 (844 compostos) apresentam maior número de compostos (réplicas 1) tal como verificado pelo software DataAnalysis. Após a identificação do número de compostos realizaram-se diagramas de Van Krevelen que permitiu visualizar a existência de regiões com maior densidade de compostos identificados. Os compostos identificados (exemplo: sorbitol, ácido propiónico, ácido benzoico, cumarina e kaempferol-3-glucuronida-7-sulfato) pertencem maioritariamente à classe dos lípidos e dos hidrocarbonetos condensados. Comparando os dois tipos de vinhos monocastas, os vinhos tintos apresentam um maior número de compostos identificados em relação aos vinhos brancos. Desta maneira foi possível a caracterização do perfil químico de vinhos monocastas, num tempo de análise curto e com preparação de amostra extremamente simples, recorrendo espectrometria de massa FT-ICR-MS. Para a análise de catequinas nos vinhos foi desenvolvida um método de análise por HPLC, adequado a vinhos e folhas de videira que permitiu identificar e quantificar estes importantes compostos. Após a preparação das amostras foi necessário optimizar o método de trabalho por forma a ser possível obter as condições óptimas à separação das várias catequinas numa mistura e a visualização e identificação das mesmas no cromatograma. Após todos os testes decidiu-se apenas trabalhar com as catequinas: catequina, epicatequina e epigalocatequina. Para a quantificação de catequinas foi necessário criar curvas de calibração usando-se uma mistura dos padrões de catequinas que foram injectados no HPLC. Após a criação das curvas de calibração e através das equações da recta da C e EC quantificaram-se todos os vinhos monocastas e as videiras. Concluiu-se que a C está presente em maior quantidade do que a EC em todas as amostras de vinhos monocastas e de videiras. Os objectivos deste trabalho foram cumpridos concluindo-se que através das técnicas usadas e com recurso a todo o software foi possível criar um trabalho que permitiu de forma completa a caracterização do perfil químico de uma amostra muito complexa como o vinho e a quantificação de um composto muito presente neste tipo de amostras e que servem de inspiração a estudos futuros.
Wine is a mixture of extremely complex chemical composition, resulting from the fermentation of grapes by yeasts namely Saccharomyces cerevisiae. The analysis of this type of samples is one of the biggest challenges of analytical chemistry that has an impact on the quality of production and on the evaluation of authenticity. number of compounds. The analysis of complex samples in a complete way in a short time and the development and implementation of analytical methodologies that make it possible, is one of the promising objectives in today's analytical chemistry and that leads to the high demand for knowledge and discovery of solutions. The main objectives of this work were, in the first place, the analysis and characterization of the chemical profile of monovarietal wines using a very precise and effective analytical technique for the characterization of wines, the mass spectrometry of cyclotronic ion resonance with Fourier transform - FT -ICR-MS. The second, the quantification of catechins in monovarietal wines and grape leaves by high performance liquid chromatography (HPLC) with two detectors: fluorescence and diode matrix. Monovarietal wines of different years, white and red, provided by the National Institute for Agricultural and Veterinary Research, I. P. - INIAV (Polo two Port), were analyzed. These wines were produced under controlled conditions and different years of production (2015-2018). Samples of monovarietal wines were prepared by dilution in MeOH. Each sample analyzed contained an internal standard, Leucine Enkephalin. The samples were subsequently analyzed by FT-ICR-MS by direct positive electrospray infusion, with 3 replicates of each wine sample. For white wine samples the number of possible compounds determined varied between 1187 and 11882 and for red wine samples the number of compounds varied between 1957 and 13591. After analysis by DataAnalysis the list of peaks was submitted to the MassTRIX portal to identify the presence of some chemical compounds in monovarietal wines. MassTRIX obtained hundreds of compounds. It was also observed that the verdelho wine 2018 (777 compounds) and the verdelho red wine 2015 (844 compounds) have a higher number of compounds (replicas 1) as verified by the DataAnalysis software. After identifying the number of compounds, Van Krevelen diagrams were made, which allowed visualizing the existence of regions with a higher density of identified compounds. The identified compounds (example: sorbitol, propionic acid, benzoic acid, coumarin and kaempferol-3-glucuronide-7-sulfate) belong mainly to the class of condensed lipids and hydrocarbons. Comparing the two types of monovarietal wines, red wines have a greater number of compounds identified compared to white wines. In this way it was possible to characterize the chemical profile of monovarietal wines, in a short analysis time and with extremely simple sample preparation, using FT-ICR-MS mass spectrometry. For the analysis of catechins in wines, an HPLC analysis method was developed, suitable for wines and grape leaves that allowed to identify and quantify these important compounds. After preparing the samples, it was necessary to optimize the working method in order to obtain the optimum conditions for the separation of the various catechins in a mixture and the visualization and identification of them in the chromatogram. After all the tests, it was decided to work only with catechins: catechins, epicatechins and epigallocatechins. For the quantification of catechins it was necessary to create calibration curves using a mixture of the catechin standards that were injected on the HPLC. After the creation of the calibration curves and through the equations of the C and EC straight line, all mono-wines and vines were quantified. It was concluded that C is present in greater quantity than EC in all samples of mono-wine and grapevines. The objectives of this work were fulfilled concluding that through the techniques used and using all the software it was possible to create a work that completely allowed the characterization of the chemical profile of a very complex sample such as wine and the quantification of a compound very present in this type of samples and that serve as inspiration for future studies.
Wine is a mixture of extremely complex chemical composition, resulting from the fermentation of grapes by yeasts namely Saccharomyces cerevisiae. The analysis of this type of samples is one of the biggest challenges of analytical chemistry that has an impact on the quality of production and on the evaluation of authenticity. number of compounds. The analysis of complex samples in a complete way in a short time and the development and implementation of analytical methodologies that make it possible, is one of the promising objectives in today's analytical chemistry and that leads to the high demand for knowledge and discovery of solutions. The main objectives of this work were, in the first place, the analysis and characterization of the chemical profile of monovarietal wines using a very precise and effective analytical technique for the characterization of wines, the mass spectrometry of cyclotronic ion resonance with Fourier transform - FT -ICR-MS. The second, the quantification of catechins in monovarietal wines and grape leaves by high performance liquid chromatography (HPLC) with two detectors: fluorescence and diode matrix. Monovarietal wines of different years, white and red, provided by the National Institute for Agricultural and Veterinary Research, I. P. - INIAV (Polo two Port), were analyzed. These wines were produced under controlled conditions and different years of production (2015-2018). Samples of monovarietal wines were prepared by dilution in MeOH. Each sample analyzed contained an internal standard, Leucine Enkephalin. The samples were subsequently analyzed by FT-ICR-MS by direct positive electrospray infusion, with 3 replicates of each wine sample. For white wine samples the number of possible compounds determined varied between 1187 and 11882 and for red wine samples the number of compounds varied between 1957 and 13591. After analysis by DataAnalysis the list of peaks was submitted to the MassTRIX portal to identify the presence of some chemical compounds in monovarietal wines. MassTRIX obtained hundreds of compounds. It was also observed that the verdelho wine 2018 (777 compounds) and the verdelho red wine 2015 (844 compounds) have a higher number of compounds (replicas 1) as verified by the DataAnalysis software. After identifying the number of compounds, Van Krevelen diagrams were made, which allowed visualizing the existence of regions with a higher density of identified compounds. The identified compounds (example: sorbitol, propionic acid, benzoic acid, coumarin and kaempferol-3-glucuronide-7-sulfate) belong mainly to the class of condensed lipids and hydrocarbons. Comparing the two types of monovarietal wines, red wines have a greater number of compounds identified compared to white wines. In this way it was possible to characterize the chemical profile of monovarietal wines, in a short analysis time and with extremely simple sample preparation, using FT-ICR-MS mass spectrometry. For the analysis of catechins in wines, an HPLC analysis method was developed, suitable for wines and grape leaves that allowed to identify and quantify these important compounds. After preparing the samples, it was necessary to optimize the working method in order to obtain the optimum conditions for the separation of the various catechins in a mixture and the visualization and identification of them in the chromatogram. After all the tests, it was decided to work only with catechins: catechins, epicatechins and epigallocatechins. For the quantification of catechins it was necessary to create calibration curves using a mixture of the catechin standards that were injected on the HPLC. After the creation of the calibration curves and through the equations of the C and EC straight line, all mono-wines and vines were quantified. It was concluded that C is present in greater quantity than EC in all samples of mono-wine and grapevines. The objectives of this work were fulfilled concluding that through the techniques used and using all the software it was possible to create a work that completely allowed the characterization of the chemical profile of a very complex sample such as wine and the quantification of a compound very present in this type of samples and that serve as inspiration for future studies.
Description
Tese de mestrado em Química, Universidade de Lisboa, Faculdade de Ciências, 2020
Keywords
Vinhos monocastas Videiras Catequinas FT-ICR-MS HPLC Teses de mestrado - 2020