Estudo do perfil interno do gargalo de garrafas e o seu impacto na oxidação do vinho

Abstract

The present curricular internship had as main objective to allow direct contact with the professional environment in the scope of the Master in Food Engineering. The internship work was developed at the company Symington Family Estates, particularly in the Quality Department of Materials and Finished Product, and later in the Wine Laboratory of the Higher School of Biotechnology of the Portuguese Catholic University of Porto The so-called premature oxidation of wines is a phenomenon that is not yet fully understood. Different factors contribute to it, leading to the development of negative effects on the wine’s taste, smell and color. One of these factors could be the internal profile of the bottleneck, one of the dimensional characteristics to consider in the bottle’s structure. The aims of the study were to determine the variability of the internal profile of the bottleneck between four bottle models (A, B, C and D) and to evaluate their impact on wine oxidation. In order to achieve the mentioned objectives, measurements were made of the internal diameter of the bottleneck from 2 mm to 50 mm depth to fifty bottles from each model. Then, in order to evaluate the impact of this variable on wine oxidation, two representative samples of each bottle model were selected and a forced aging was simulated in the laboratory (T = 40ºC with addition of Cu2+ and Fe2+ to the wine). After twenty-one days, the analytical characterization of the samples was carried out through oxidation markers namely pH, free and total sulfur dioxide, aldehydes and ketones, volatile compounds and oxidation-reduction potential. The results of the first study demonstrated that there are significant differences in the mean internal diameter of the bottleneck between the four bottle models at all depths tested. In the second study, there were differences between the models and between replicates of the same model, evidencing the impact of the study variable on wine oxidation. It was concluded that there is internal profile heterogeneity of the bottleneck between the four bottle models that led to different oxidation patterns in the representative samples of the study. The constant development of future work in the sealing system is crucial to better understand it impact on the wine oxidation. This study has a great theoretical and commercial impact with regard to the production of wine packaging and to understand the oxidation phenomenon as a result of an interaction of exogenous and endogenous factors.

Date of Award	30 Nov 2018
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Cláudia Santos (Supervisor) & César Ferreira (Co-Supervisor)