WHITE WINES OXIDATIVE STABILITY: A 2-VINTAGE STUDY OF CHARDONNAY CHAMPAGNE BASE WINES AGED ON LEES IN BARRELS

Under standard wine tasting conditions, volatile organic compounds (VOCs) responsible for the wine’s bouquet progressively invade the glass headspace above the wine surface. Most of wines being complex water/ethanol mixtures (with typically 10-15 % ethanol by volume), gaseous ethanol is therefore undoubtedly the most abundant VOC in the glass headspace [1]. Yet, gaseous ethanol is known to have a multimodal influence on wine’s perception [2]. Of particular importance to flavor perception is the effect of ethanol on the release of aroma compounds into the headspace of the beverage [1].

Climate change has brought several impacts that are becoming increasingly intense during the last few years and put at risk the quality of the berries or even the plant’s sustainability. Such extreme climatic events impact the composition of the wine while modulating its quality and the consumer preferences (Tempère et al., 2019). The three most important changes that take place in the must are: 1) decrease acidity, 2) increase of the concentration of sugar, hence increase of alcohol in the wine, and 3) modification
of the sensory balance and the development for example of cooked fruit aromas.

Aging wine on lees is a consolidated practice during which some yeast components (e.g., polysaccharides,
proteins, peptides) are released and solubilized in wine thus, affecting its stability and quality.
Apart from the widely studied mannoproteins, the role of other yeast components in modulating wine
characteristics is still scarce. Wine peptides have been studied for their contribution to taste, antioxidant,
and antihypertensive potentials. However, the peptides detected in wine can be influenced by the
interaction between yeasts and grape components.

The phenolic compounds of red wines represent a source of numerous benefits for human health, which is why they are a constant subject of scientific research. Winemaking in Serbia has a growing economic significance, with particularly autochthonous varieties included [1]. This research identifies and quantifies phenolic compounds of Serbian red varietal wines of Prokupac and Black Tamjanika varieties. Quantification of the level of phenolics has been conducted, including molecular tannins [(+)-catechin, (-)-epicatechin, procyanidin dimers B1, B2, B3, B4], molecular anthocyanins, and the mean degree of polymerization of tannins by HPLC by UV detection, total antioxidant capacity via spectrophotometric methods and chromatic characteristics via CIELAB.

It is well known that the vinification of grapes at full maturation can produce rich, full-bodied wines,
with intense and complex flavour profiles. However, the juice obtained from such grapes may have very
high sugar concentration, resulting in wines with an excessive concentration of ethanol. In addition, the decoupling between technological maturity and phenolic/aromatic one due to global warming, exacerbates this problem in some wine-growing regions. In parallel with the increase of the mean alcohol content of wines on the market, also the demand for reduced alcohol beverages has increased in recent years, mainly as a result of health and social concerns about the risks related to the consumption of alcohol.