Phenolic contents, antioxidant activity and colour density of Slovak Pinot Noir wines

<p class="042abstractstekst"><span lang="EN-US">Recent studies show that wine contains more than thousand different compounds that could come from grapes, or could be formed in the process of winemaking and maturing. The most abundant compounds in wines are polyphenols, which affect sensory properties such as colour, taste and aroma, but also has antioxidant properties. The aim of this study was to determine total polyphenol and total anthocyanin contents, and to evaluate antioxidant effects and wine colour density of red wines ‘Pinot Noir’ produced in Slovakia. Thirteen analysed, bottled, quality dry ‘Pinot Noir’ wines with origin in various Slovak wine regions were purchased in retail network, to provide that analysed samples of wine would have the same properties as wines that are consumed by common consumers. The content of total polyphenols in analysed ‘Pinot Noir’ wines ranged from 1458 to 3324 mg GAE l^-1, while contents of total anthocyanins ranged from 43.6 to 279.6 mg l^-1. Antioxidant activities ranged from 80.2 % to 85.3 % inhibition of DPPH and wine colour density ranged from 0.679 to 1.495. The highest total polyphenol content, total anthocyanin content, and wine colour density was determined in wines from the south Slovakia winegrowing region, while the highest antioxidant activity in wines from Nitra winegrowing region. Results did not show significant differences among studied parameters in wines from different winegrowing regions. Results showed that Slovakian ‘Pinot Noir’ wines have characteristics comparable with ‘Pinot Noir’ wines from other countries.</span></p><div id="OKAYFREEDOM_INJECTED" style="display: none;"> </div><script type="text/javascript" src="chrome-extension://hfnbbbkabnehoejfhcbbhdicagcoobji/web/libs/ciuvo-addon-sdk.min.js"></script>

Relationship between lactic acid bacteria, malolactic fermentation and wine colour

Some phenolic acids can either inhibit or stimulate the growth of Oenococcus oeni and other lactic acid bacteria (LAB) in wine. It has been observed that some LAB metabolism could have an influence on wine colour. In this article, some of the relationships between LAB, malolactic fermentation (MLF) and phenolic compounds are summarised; these relationships are important for the selection of LAB to make starter cultures and are of interest for wineries in terms of its effect on wine colour.

Characterisation of Extracts Obtained from Unripe Grapes and Evaluation of Their Potential Protective Effects against Oxidation of Wine Colour in Comparison with Different Oenological Products

Unripe grapes (UGs) are a waste product of vine cultivation rich in natural antioxidants. These antioxidants could be used in winemaking as alternatives to SO2. Three extracts were obtained by maceration from Viognier, Merlot and Sangiovese UGs. The composition and antioxidant activity of the UG extracts were studied in model solutions at different pH levels. The capacity of the UG extracts to protect wine colour was evaluated in accelerated oxidation tests and small-scale trials on both red and white wines during ageing in comparison with sulphur dioxide, ascorbic acid and commercial tannins. The Viognier and Merlot extracts were rich in phenolic acids while the Sangiovese extract was rich in flavonoids. The antioxidant activity of the extracts and commercial tannins was influenced by the pH. In the oxidation tests, the extracts and commercial products showed different wine colour protection capacities in function of the type of wine. During ageing, the white wine with the added Viognier UG extract showed the lowest level of colour oxidation. The colour of the red wine with the UG extract evolved similarly to wine with SO2 and commercial tannins. The obtained results indicated that natural and healthy UG extracts could be an interesting substitute for SO2 during wine ageing.

Impact of oak wood modalities on the (non)-volatile composition and sensory attributes of red wines

During fermentation or ageing of wines, oak wood is commonly used in form of barrels, casks or derived oak products (chips, winewoods, tankstaves, among others). It is well known that aroma, structure, astringency, bitterness, aromatic persistence and colour may change as a result of wine‒wood contact. A full-scale experimentation was performed under different oak ageing conditions in order to evaluate colour, phenolic, aromatic and sensory differences among final red wines (9‒months ageing). Oenological parameters and wine colour were not impacted by ageing modality. At the end of ageing, no differences were found in total phenolic and tannin contents. Regardless of the ageing modality, total content and profile of fruity volatiles were globally maintained with regard to control (≥ 86 %). In contrast, the higher the surface of wine‒wood contact per unit of wine volume, the greater the extraction of woody aromas. Thus, barrels led to wines with the highest level of woody aromas (515‒864 µg/L), followed by cask modalities (430‒470 µg/L). From a sensory point of view, descriptors highlighting the woody character of wine (vanilla, spicy) were enhanced in all oak‒aged wines when compared to control. However, our results indicate that a masking effect of fruity aroma by oak wood did not occur, since all modalities were perceived as fruity as the control. Thus, each oak ageing modality may lead to wines with a different woody character, without no impact on fruity perception, allowing wineries to achieve the targeted aromatic profile, good structure and just the right balance between fruity and woody aromas.

Effect of wine maturing on the colour and chemical properties of Chardonnay wine

Untreated chardonnay wine was used as the raw material for this study. The wine samples were divided into three groups and monitored over 32 weeks. Three ways of wine maturation were used: glassware, wooden barrel and the addition of oak chips for 6 weeks, which can significantly increase total polyphenols (P &lt; 0.05) and flavonoids (P &lt; 0.05) concentration. The use of oak shavings had a comparable effect to the oak barrels. The use of oak shavings can replace wood barrels in the maturation process. The oak shavings also achieved lower oxygen concentration (P &lt; 0.05) in wine. Ageing the Chardonnay increased (P &lt; 0.05) the polyphenol concentration and had an impact on the wine colour under the different maturation conditions.

Influence of supplementing red wine with oak staves of various ellagitannin release potentials and different micro-oxygenation doses on wine colour and phenolic and volatile composition

Aim: The aim of the study was to evaluate the effect on wine colour and phenolic and volatile composition of supplementing a red wine with different oak staves - selected using a non-invasive measurement method based on infrared spectrometry (Oakscan system) - during a micro-oxygenation treatment.Methods and results: Aliquots of 165 liters of a Merlot wine were micro-oxygenated at two doses of oxygen (2.5 and 5.0 mg of O2/L.month) in the presence or not of oak staves of different potential ellagitannin release (PER) for three months. Micro-oxygenation generally increased colour intensity and stability, probably because it favours the formation of new pigments. The presence of staves increased the total phenolic index and the ellagitannin concentration and encouraged the combination of anthocyanins with flavanols. The greater the PER of the staves, the greater this effect was. Finally, the micro-oxygenation dose only affected the concentration of total furanic compounds, whereas the PER of the staves seemed to determine the concentrations of furanic compounds, volatile phenols and β-methyl-γ-octalactones. To be specific, the lower the PER of the staves, the higher the concentration of β-methyl-γ-octalactones (coconut notes) and the lower the concentration of furanic compounds (toasted nut notes) and volatile phenols (smoked notes). A sensory analysis of the wines confirmed this trend.Conclusions: The main conclusion is that it is possible to use a non-invasive measurement method based on infrared spectrometry oak staves for their potential release of ellagitannins, as well as different volatile substances.Significance and impact of the study: These results indicate that by choosing the staves winemakers can modulate both the structure and the aromatic profile of their wines.