Characterization and biological effects of extracts from winery by-products

Grapevines have traditionally been grown in semi-arid areas, but viticulture is now compromised by climate change. Therefore, it is necessary to implement environmentally friendly viticulture practices to adapt grapevines to current climatic conditions. In this context, organic mulches offer many benefits, such as reduced soil erosion and increased organic matter, soil water content and crop productivity. However, these practices must not compromise grape and wine quality. Therefore, the objective of this study was to evaluate the effect on wine physicochemical and phenolic composition and sensorial properties of different soil management practices on the vine row. Over four years, five soil treatments were examined in two different vineyards.

Oenological tannins are products extracted from various botanical sources, such as mimosa,
acacia, oak gall, quebracho, chestnut and tara. The polyphenolic component is obtained through a solid-liquid extraction also using specific solvents, then removed by evaporation or freeze-drying. Tannins are employed in two phases of winemaking, during the pre-fermentative phase or during fining with different purposes such as modulate antioxidant activity, colour stabilization, bacteriostatic activity, protein stabilization and modulation of sensory properties. To date, the current regulatory framework is not very clear. In fact, the Codex Alimentarius classifies commercial tannins as “food additives” but also as
“processing aids”. The main distinction is that “additives” have a technological function in the final food, whereas “processing aids” do not. In this sense, oenological tannins, despite the technological treatments, could contain aromatic compounds of the botanical species they belong to and release them to the wine.

Context and purpose. Nitrogen (N) is crucial for plant development but is used inefficiently, with only 30–40% of the fertilizer assimilated by crops, leading to significant environmental losses.

Remote sensing applications in viticulture have been a research theme now for nearly two decades, becoming a valuable tool for vineyard management. Metrics produced using remotely sensed images of vineyards have yielded relationships with grape quality and yield that can help optimise vineyard performance

The online monitoring of fermentative aromas provides a better understanding of the effect of temperature on the synthesis and the loss of these molecules. During fermentation, gas and liquid phase concentrations as well as losses and total productions of volatile compounds can be followed with an unprecedented acquisition frequency of about one measurement per hour. Access to instantaneous production rates and total production balances for the various volatile compounds makes it possible to distinguish the impact of temperature on yeast production (biological effect) from the loss of aromatic molecules due to a physical effect³.