Molecular approaches for understanding and modulating wine taste

Light-struck taste (LST) is a wine fault that can occur in white and sparkling wines when exposed to light. This defect is mainly associated to the formation of methanethiol and dimethyl disulfide due to light-induced reactions involving riboflavin (RF) and methionine [1]. The presence of RF in wine is mainly due to the metabolism of yeast [2] which fermenting activity can be favoured by using yeast derivative products (YDPs) as nutrients. Nonetheless, a previous study showed the addition of YDPs before the alcoholic fermentation (AF) led to higher concentrations of RF in wines [3]. Due to the widespread use of YDPs in the winemaking process, this study aimed to understand the possible relation between the content of RF in wine and the YDP adopted as nutrient for AF.

Many wine styles require moderate or extended ageing to ensure optimal consumer experience. However, few consumers have the interest or ability to age wine themselves, and holding wine in optimal conditions for extended periods is expensive for producers. A study was conducted on the use of ul-trasound energy on wine, with particular reference to its impact on sensory and chemical profiles. The OIV has authorised the use of ultrasound for processing crushed grapes (must) in Resolution OENO 616-2019, but not yet for finished wine1,2.

In economics, the perception of wine quality is not limited to sensorial characteristics: an indication of the region of production significantly affects the perception of quality and consumers’ WTP ([1]; [2]). However, [3] or more recently [4] show that even if a wine has an organic label, the taste of wine remains the predominant criterion in consumer preferences. The contribution of our experiment is to evaluate the impact of responsible attributes (organic label, Non Added Sulfites, HVE certification) on the appreciation of several red wines on the market. More than 280 consumers participated to the present study and they perform 25 tastings divided into 5 different sessions. 20 different red wines from Bordeaux Area are tasted.

Plants in their natural environment are in continuous interaction with large numbers of potentially pathogenic and beneficial microorganisms. Depending on the microbe, plants have evolved a variety of resistance mechanisms that can be constitutively expressed or induced. Phytoalexins, which are biocidal compounds of low to medium molecular weight synthesized by and accumulated in plants as a response to stress, take part in this intricate defense system.1,2
One of the limitations of our knowledge of phytoalexins is the difficulty of analyzing their spatial responsiveness occurring during plant- pathogen interactions under natural conditions.

Prior to winemaking, organic or mineral nitrogen compound concentrations are usually measured in the vineyard and in grape musts. These indicators facilitate vine cultivation decisions, usually through yield or vigor. During vinification, yeast and bacteria metabolize nitrogen compounds in the musts in order to generate biomass. After fermentation, the microorganisms rerelease a part of this nitrogen as soluble compounds into the wines. Another part remains bound in the lees and can be lost during racking. The must’s natural nitrogen quantities, additional supplements during fermentation, and lees contact management enhance the release of nitrogen compounds to the wines. During ageing these nitrogen compounds – primarily the amino acids – are implicated in the generation of odorous compounds such as heterocycles(1).