Effect of non-wine Saccharomyces yeasts and bottle ageing on the release and generation of aromas in semi-synthetic Tempranillo wines

Armenia, as one of the ancient centers of grapevine domestication, harbors a unique repository of genetic diversity in its indigenous and wild grapevine populations, highlighting a key role in the millennia-lasting history of grape cultivation in the Southern Caucasus (Margaryan et al., 2021).

From fruit set to ripening, the grape berry mesocarp experiences a wide range of dynamic physical, physiological, and biochemical changes, such as mesocarp cell death (MCD) and hydraulic isolation. The premature occurrence of such events is a characteristic of the Niagara Rosada (NR) variety, utilised as table grapes and winemaking. In our opinion, the onset of ripening would not cause MCD, but a down-regulation of respiratory enzymes during the early loss of cell viability, while maintaining membrane integrity. For this, we investigated three distinct developmental stages (green (E-L33), veraison (E-L35), and ripe (E-L39)) of NR berries by label-free proteomics, enzymatic respiratory activity and outer mesocarp imaging. Cell wall-modifying proteins were found to accumulate differently throughout ripening, while cytoplasmic membranes continue intact.

Grapevine downy mildew, caused by Plasmopara viticola, is a devastating disease worldwide. Most commercially important cultivars of the European grapevine are highly susceptible and therefore require the recurrent application of synthetic fungicides to control the disease, copper being the most frequently used. However, with European Union goals to lower their usage, there is a need to develop innovative and sustainable strategies. In this respect, seaweeds have proven to have great potential as phytosanitary agents, in addition to promoting plant growth and stress-tolerance.

During red wine ageing or conservation, color and taste change and astringency tends to reduce. These changes result from reactions of flavan-3-ols and/or anthocyanins among which condensation reactions with acetaldehyde are particularly important. The full characterization of these reactions has not been fully achieved because of difficulties in extracting and separating the newly formed compounds directly from wine. Model solutions mimicking food products constitute a simplified medium for their exploration, allowing the detection of the newly formed compounds, their isolation, and their structure elucidation.

AIM: Glutathione (GSH) is a non-protein thiol naturally present in grape berries and produced by yeasts during fermentation. It has a strong antioxidant activity, thus can be added during winemaking to limit the oxidative phenomena of wine, preserving sensory characteristics and stability, ultimately promoting a healthier product by reducing the need for SO2 addition.