ANTIOXIDANT CAPACITY OF INACTIVATED NON-SACCHAROMYCES YEASTS

Cognac is a famous spirit produced in southwest France in the region of the eponymous town from wines mainly from Vitis vinifera cv. Ugni blanc. This variety gives very acidic and poorly aromatic base wines for distillation which are produced according to a very specific procedure. Grapes are picked at low sugar concentrations ranging 13-21 °Brix and musts with high turbidity (>500 NTU) are fermented without sulphite addition [1]. Fermentative aromas, as esters and higher alcohols, are currently the main quality markers considered in Cognac spirits.

Wine complexity is considered a multidimensional yet equivocal sensory percept. This project uncovered sensory attributes Australian Chardonnay wine consumers associate with Chardonnay wine complexity
and correlations between expert and consumer perceived wine complexity and preference. A
wine consumer test examined 6 Australian Chardonnay wines of three complexity levels designated low (LC1&2), medium (MC1&2), and high (HC1&2) by an expert panel (n = 8) using a benchtop sensory task. Consumers (n = 81) rated their perceived liking using a 9-point hedonic scale; wine complexity with a 5-point scale anchored “low”, “low-medium”, “medium”, “medium-high”, and “high” and lastly, profiled the wines using Rate-All-That-Apply (RATA). Psychographic segmentation with the Fine Wine Instrument
(FWI) generated three segments; Wine Enthusiasts (WE n=29), Aspirants (ASP n=40) and No- Frills (NF n=12).

Over the last few years, several tools have been developed to reduce the quantity of sulfites used during winemaking, including bioprotection. Although its effectiveness in preventing the development of spoilage microorganisms has been proven, few data are available on the impact of sulfite substitution by bioprotection on the final product. The objective of this study was therefore to characterize Chardonnay wines with the addition of sulfite or bioprotection in the pre-fermentation stage. The effects of both treatments on resulting matrices was evaluated at several scales: analysis of classical oenological parameters, antioxidant capacity, phenolic compounds, non-volatile metabolome and sensory profile.

The evolution of wine during bottle ageing has been of great interest to ensure consistent quality over time. While the role of wine closures on the amount of oxygen is well-known [1], closures could also play other roles such as the scalping phenomenon of flavour compounds. Flavour scalping has been described as the sorption of flavour compounds by the packaging material, which could result in losses of flavour intensity. It has been reported in the literature that volatile sulphur compounds (VSC) can be scalped on wine closures depending on the type of closure (traditional and agglomerated cork, screw-cap, synthetic [2]).

Lugana wines are made from Turbiana grapes. In recent times, many white and rosé wines are bottled and stored in flint glass bottles because of commercial appeal. However, this practice could worsen the aroma profile of the wine, especially as regards the development of volatile sulfur compounds (VSCs). This study aims to investigate the consequences of exposure to light in flint bottles on VSCs profile of Lugana wines fermented with two different yeasts and with different post-fermentation residual nitrogen.