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O estágio curricular foi realizado no âmbito da componente Tese/Estágio do Mestrado em Engenharia Alimentar visando o contacto direto com o meio profissional, tendo sido desenvolvida a componente prática no Departamento de Qualidade de Materiais e Produto Acabado (QMPA) da Symington Family Estates, em parceria com o Laboratório de Vinhos da Escola Superior de Biotecnologia da Universidade Católica Portuguesa do Porto (ESB-UCP). A oxidação aleatória de vinhos é um fenómeno ainda não compreendido na integra que impactua negativamente o produto final a nível sensorial (sabor, aroma e cor), sendo as alterações físico-químicas passíveis de serem percecionadas pelo consumidor. Os objetivos do estágio consistiram em determinar a homogeneidade do perfil de garrafas de um mesmo modelo, estudar o impacto da rolha e da garrafa no que concerne a oxidação aleatória do vinho e comparar o efeito da adição de metais ao vinho. Afim de alcançar os objetivos enunciados, efetuou-se medições ao diâmetro interno do gargalo, selecionou-se as garrafas que seriam posteriormente submetidas a envelhecimento forçado (50 ºC durante 40 dias) com ou sem adição de metais, assim como, qual o tipo de fecho a aplicar, rolha de cortiça natural ou rolha microgranulada. Posteriormente, procedeu-se à caracterização analítica das amostras através de marcadores de oxidação, nomeadamente, pH, dióxido de enxofre livre e total, aldeídos e cetonas, compostos voláteis e potencial de oxidação-redução, entre outros, e, comparou-se face às amostras controlo que permaneceram a temperatura ambiente durante o mesmo período de tempo. Os resultados demonstraram que existem diferenças estatisticamente significativas no que diz respeito ao perfil dos gargalos das garrafas de um mesmo modelo. Adicionalmente, segundo as análises químicas executadas evidencia-se o impacto das variáveis garrafa e fecho no que concerne à oxidação do vinho, isto é, tanto o grau de heterogeneidade do gargalo como o tipo de fecho aplicado culminam na geração de padrões de oxidação distintos. O presente estudo contribui para a compreensão do fenómeno de oxidação do vinho como fruto da interação do trinómio garrafa-rolha-vinho.
The curricular internship was carried out within the scope of the Thesis/Internship component of the Master's Degree in Food Engineering, aiming towards the direct contact with the professional environment. The practical component was developed at the Quality Department of Materials and Finished Product (QMPA) of Symington Family Estates in partnership with the Laboratory of Wines of the Superior School of Biotechnology - Portuguese Catholic University of Porto (ESB-UCP).Random oxidation of wines is a phenomenon not yet understood completely that impacts negatively the final product at sensorial level (flavor, aroma and color) and these physical-chemical changes can be perceived by the consumer. The objectives of the study were to determine the homogeneity of the profile of bottlenecks of one same model, to evaluate the impact of the cork and the bottleneck regarding random oxidation of wine and to compare the effect of the addition of metals to the wine. To achieve the stated objectives, measurements were made to the internal diameter of the bottleneck, the bottles selected afterwards were later subjected to forced aging (50 ° C for 40 days) with or without addition of metals. Additionally, the type of closure to be applied, natural cork stopper or microgranulated stopper, was also selected according to the experimental design. Subsequently, the analytical characterization of the samples through oxidation markers, namely, pH, free and total sulfur dioxide, aldehydes and ketones, volatile compounds and oxidation-reduction potential, among others, was carried out and the results were compared to the data obtained from the analysis of control samples which remained at room temperature for the same period. The results showed that there are statistically significant differences with respect to the profile of bottle necks of the same model. In addition, according to the chemical analyzes performed, the impact of the bottle and closure on wine oxidation is evident, that is, both the degree of heterogeneity of the bottleneck and the type of closure applied contribute to the generation of different oxidation patterns. The present study contributes for better understanding the phenomenon of wine oxidation as a result of the trinomial bottle-cork-wine interaction.
The curricular internship was carried out within the scope of the Thesis/Internship component of the Master's Degree in Food Engineering, aiming towards the direct contact with the professional environment. The practical component was developed at the Quality Department of Materials and Finished Product (QMPA) of Symington Family Estates in partnership with the Laboratory of Wines of the Superior School of Biotechnology - Portuguese Catholic University of Porto (ESB-UCP).Random oxidation of wines is a phenomenon not yet understood completely that impacts negatively the final product at sensorial level (flavor, aroma and color) and these physical-chemical changes can be perceived by the consumer. The objectives of the study were to determine the homogeneity of the profile of bottlenecks of one same model, to evaluate the impact of the cork and the bottleneck regarding random oxidation of wine and to compare the effect of the addition of metals to the wine. To achieve the stated objectives, measurements were made to the internal diameter of the bottleneck, the bottles selected afterwards were later subjected to forced aging (50 ° C for 40 days) with or without addition of metals. Additionally, the type of closure to be applied, natural cork stopper or microgranulated stopper, was also selected according to the experimental design. Subsequently, the analytical characterization of the samples through oxidation markers, namely, pH, free and total sulfur dioxide, aldehydes and ketones, volatile compounds and oxidation-reduction potential, among others, was carried out and the results were compared to the data obtained from the analysis of control samples which remained at room temperature for the same period. The results showed that there are statistically significant differences with respect to the profile of bottle necks of the same model. In addition, according to the chemical analyzes performed, the impact of the bottle and closure on wine oxidation is evident, that is, both the degree of heterogeneity of the bottleneck and the type of closure applied contribute to the generation of different oxidation patterns. The present study contributes for better understanding the phenomenon of wine oxidation as a result of the trinomial bottle-cork-wine interaction.
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Keywords
Oxidação Vinho Gargalo Aleatória Cortiça Fenólicos Random oxidation Wine Bottleneck Cork Phenolics