Contribution and importance of wine spirit to the port wine final quality—initial approach

Abstract

The commercial wine spirit used for this study revealed that the aldehyde content mainly comprises acetaldehyde but other aldehydes such as propionaldehyde, 2-methylbutyraldehyde, isovaleraldehyde, methylglyoxal, benzaldehyde and others are also present in significant amounts. A typical grape must was used to assess the influence of wine spirit in the analytical and sensorial characteristics of fortified wines. Decreasing levels of anthocyanins, as well the increase in the red colour and tanning capacity, were observed, and seem to be positively correlated with the increase of the aldehyde content present in the wine spirits used to fortify the must. Using the CIE L * a * b * system, this aldehyde content present in the spirit used seemed to be correlated with the decrease of the wines' lightness (darkening effect), the displacement of the hue angle to higher values (yellowing effect) and the increase of the chromaticity (colour saturation) of the wines.

Chemical transformations of anthocyanins yielding a variety of colours (Review)

“…propionaldehyde, isovaleraldehyde and benzaldehyde) and could also contribute to the wine colour change (Rogerson and de Freitas 2002;Pissarra et al 2005b). However, apart from the An-ethyl-Fl adduct (1), other An-alkyl-Fl compounds (2-5) have never been detected in wines.…”

Wine-Inspired Chemistry: Anthocyanin Transformations for a Portfolio of Natural Colors

“…In the case of fortified wines such as Port wines, this compound and other aldehydes (propionaldehyde, 2-methylbutyraldehyde, isovaleraldehyde, methylglyoxal, benzaldehyde) are present in higher amounts due to the addition of a wine spirit (40-260 mg/L of acetaldehyde) to stop the fermentation. 31 This increases the possibilities of reactions between anthocyanins and flavanols in wines leading to the formation of anthocyanin-alkyl/aryl-flavanol adducts as reported in the literature. 26 The formation of these dimeric adducts starts with the protonation of the aldehyde under acidic conditions, followed by its addition to the nucleophilic carbon C-6 or C-8 of a flavanol unit (Scheme 5A).…”

Port Wine: Production and Ageing

“…Acetaldehyde is the main aldehyde (90%) present in wines as a result of yeast metabolism during the first stages of alcoholic fermentation, being also produced throughout the wine ageing process from ethanol oxidation [52]. In fortified wines like Port wines, this compound and other aldehydes (propionaldehyde, 2-methylbutyraldehyde, isovaleraldehyde, methylglyoxal, benzaldehyde) are present in higher amounts due to the addition of wine spirit (40-260 mg/L of acetaldehyde) to stop the alcoholic fermentation [53]. Ethyl-linked products, including ethyl-linked flavanols [54,55] and ethyl-linked anthocyanin-flavanol pigments (XVII) [55] have been detected in wines (Figure 2).…”