Development of bioprospecting tools for oenological applications

How could the wine industry be more sustainable? To answer this, an Interreg French-Swiss project gathered researchers to help a French keg producer and a Swiss wine distributor make their innovation more ecological, social and economical. What innovation? A reusable plastic keg with a disposable airtight pouch inside.

Winemaking generates various types of residues (vine shoots, stalks, pomace, wine lees and filtration cakes) which can have a notable environmental and economic impact. Wine by-products are rich in bioactive compounds and therefore their valorization can be beneficial on different levels.

The advance in maturation of wine grapes is an important climate change risk related effect that could affect warm regions like Portuguese Douro Wine Region. Indeed, the climate analysis over the past years registered a decrease in the precipitation, significant higher average temperatures, and a more frequent occurrence of extreme weather events, including heat waves. In these conditions the length from anthesis until maturation is shortened and the uncoupling of technical and phenolic maturity results in berries with higher sugar concentration (and lower acidity), but lower anthocyanins, tannins, and total phenolic concentration, which produce unbalanced wines.
In this work, an innovative strategy of crop forcing, based on forcing vine regrowth after a second pruning of green shoots, was tested, aimed at delaying ripening until the temperature becomes lower and, therefore, preventing acidity loss and increasing anthocyanin-to-sugar ratio. The experiments were conducted in 2019 and 2020 in a commercial vineyard of ‘Touriga Nacional’ located in the Douro Region. Crop forcing was conducted 15 (CF1) to 30 (CF2) days after fruit set. Vines pruned with conventional methods were used as control (CF0). Results confirmed that fruit ripening was shifted from the hot season (August/September), until a cooler period (October through early-November). At harvest, grapevine berries from CF1 and CF2 presented lower pH and higher acidity, than control, with no significant differences in colour intensity and phenolic levels composition. Sugar content was lower in CF2-treated vines in both seasons. However, in CF-treated vines the number and size of clusters were significantly lower (up to 88% reduction) than in control plants. A metabolomics analysis of mature berries from CF-treated vines and control is underway. Crop forcing was indeed effective in producing a more balance berry composition but severely reduced grapevine yield,

Winemaking is a globally significant industry in the field of food technology (218 mhL of wine estimated for 2024 harvest) [1], which activity produces tons of by-products annually, including pomace (pulp, stems, seeds, skins), lees, organic acids, CO2, and water [2].

In viticoltura, la comprensione dell’influenza della temperatura dell’aria sulla dinamica della maturazione assume importante rilievo in relazione all’ ottimizzazione dell’ epoca di raccolta da cui dipende in modo significativo la qualità del prodotto finale.