PREVALENCE OF OAK-RELATED AROMA COMPOUNDS IN PREMIUM WINES

Wines made from Muscat d’Alexandria grapes exhibit a high haze risk. For this reason, they are systematically treated with bentonite, on the must and sometimes also on wine. In most oenological labora-tories and in companies (trade, cooperatives, independent winegrowers), the test that is by far the most widely used, on a worldwide scale, remains the heat test at 80°C for 30 minutes to 2 hours (and some-times up to 6 hours). The tannin test (sometimes coupled with a heat treatment) and the Bentotest are still used. In this study, we show that all these tests give much higher estimates of the haze risk than the risk assessed by a 24-48h treatment at 42°C, which represents a heat wave.

In this work we briefly present a microfluidic device aiming to sort yeast cells according to their morphology. The technology is based upon microfluidic chips made out of Polydimethylsiloxane and glass using soft lithography processes and replica molding. The microfluidic device was used for encapsulating single yeast cells in liquid droplets containing growth medium. Liquid droplet containing yeast cells were sorted using a real time imaging and decision-making process.

Sauvignon blanc is characterized by distinctive aromas, both fruity and herbaceous. The “green” character has been attributed to the methoxypyrazines, while the “fruity” character is associated with polyfunctional mercaptans . Polyfunctional mercaptans are of great significance due to their high impact on wines and associated low perception thresholds.
Elemental sulfur (S⁰) is widely used to protect grapevines from powdery mildew.

Bordeaux is the largest appellation vineyard in France. This contrasting vineyard with varied terroirs offers all styles of wine, resulting from the blending of several grape varieties. If these different profiles make the renown of Bordeaux wines, it can appear as a constraint when the aim is to study Bordeaux wines in their diversity. The selection of a representative sample can be performed by a sensory analysis carried out by trained panelists or by wine professionals, which can take several forms: consensus among experts, conventional descriptive analysis, typicality or quality evaluation. However, because of time, economic, and logistical constraints, these methods have limited applications. As an alternative to classical descriptive analysis, more intuitive methods that do not require training have been proposed recently to describe wines using an expert panel such as Napping, Free Choice or Flash Profiling, CATA or RATA.

Atmospheric oxygen (O₂) generates oxidation in wines that affect their physicochemical and sensory evolution. The O₂ uptake in the different winemaking processes is generally considered to be negative for the sensory characteristics of white and rosé wines. Wine racking is a critical point of O₂ uptake, as the large surface area of the wine exposed during this operation and the inability to maintain an effective inert gas blanket over it.
The aim was to study the uptake of O₂ during the racking of a model wine as a reference and to compare with purging the destination tank with different inert gases.