Impacto do perfil da garrafa e da rolha na oxidação aleatória do Vinho do Porto Vintage

Abstract

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.

Date of Award	21 Jan 2019
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Santos Cláudia (Supervisor)