Study of the impact of the wine closure on the sensory and chemical characteristics of red wines, in particular mouthfeel sensations

Abstract

Mouthfeel sensations such as astringency, texture, acidity, heat and body, influence the sensory character of wines, in particular red wines. Several studies indicate that the type of closures used in bottling wine may influence the sensory profile of the wine, through oxygen permeability, which influences oxidation reactions, and/or through the reaction of the closure material itself with the wine during storage. The present study was carried out in the context of a collaboration between Amorim Cork, SA, and Escola Superior de Biotecnologia-UCP. The main objective of this collaboration, held between March and December 2023, was to study the impact of different cork stoppers mainly in mouthfeel sensations of bottled red wines from different countries and regions. To this end a sensory panel was selected and trained, and sensory tests (duo-trio discrimination tests and descriptive sensory tests) were carried out to detect sensory perceptible differences between commercial wines bottled with different closures and to determine their in-mouth sensory profile. Additionally, the same wines were subjected to physical-chemical analysis performed in external laboratories. The measured physical-chemical parameters were free and total sulfur dioxide, the total polyphenol index (TPI), color intensity (CI), wine color tonality (CT) and volatile organic compounds (VOCs): aldehydes, furans, ketones and some esters. These parameters were previously described in the literature as indicators of the oxidation state of the wine and may be influenced by packaging conditions, namely the closures used in this study. The results thus obtained were statistically analyzed using a Kruskal-Wallis test. The sensory discrimination tests performed uncovered the existence of perceptible differences between the wines bottled with different stoppers in six of the eight sensory sessions held, mainly between the wine bottled with natural cork stoppers and with the technical cork stoppers (microagglomerated or discs). These differences were related to differences in the intensity of sensory mouthfeel attributes of these wines, as shown by uni and multidimensional analysis performed of the sensory profile results. For most wines bottled with different stoppers no significant differences regarding free and total SO2, total polyphenol index and colour parameters (CI and CT) were observed. Significant differences were found for some wines bottled with different stoppers regarding some VOCs (phenylacetaldehyde, decanal, β-cyclocitral, furfural, hexyl acetate, diethyl succinate, ethyl octanoate and ethyl decanoate). In both cases, however, none of the physical-chemical parameters analyzed allowed the identification of any trend relating the differences in the wine composition with the cork type.

Date of Award	22 Dec 2023
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Maria João Monteiro (Supervisor) & Maria Paula do Amaral Alegria Guedes de Pinho (Co-Supervisor)