Grape pomace, an active ingredient at the intestinal level: Updated evidence

Nitrogen (N) is quite important nutrient in grapevine development and must quality, but under Mediterranean climatic conditions, available soil water (ASW) during grapevine development can also influence vigour and must quality. The aim was to determine the influence of soil nitrate (NO3-) availability on N foliar, yield, and must quality in vineyards with similar available water holding capacity (AWC). For this purpose, four cv. Tempranillo (Vitis vinifera L.) vineyards were selected. All of them are placed in Uruñuela municipality (La Rioja, Spain), separated less than 2.5 km and in a slope <1 %, in soils with similar soil chemistry properties and with similar rooting depth (ranging between 105 cm and 110 cm).

Grape composition is strongly influenced by climate conditions. Their expected modifications in near future, notably because of increased temperatures, could significantly modify the biochemical composition of berries at harvest, and thus wine typicity and quality. Elevated temperatures favor sugar accumulation in grapes, enhance malic acid degradation and modify the amino acid content. They also reduce significantly anthocyanin accumulation in Merlot, leading to the imbalance between anthocyanins and sugars, while no significant effects on final anthocyanin levels were reported in Tempranillo[1] and finally affect aromas or aroma precursors.

The production of most red wines that are sold involves an alcoholic fermentation carried out by yeasts of the Saccharomyces genus, and a subsequent fermentation carried out by lactic bacteria of the Oenococus oeni species after the first one is fully completed. However, the traditional process can face complications, which can be more likely in grape juices with high levels of sugar and pH. Because of climate change, these situations are more frequent in the wine industry. The main hazards in those scenarios are halts or delays in the alcoholic fermentation or the growth of unwanted bacteria while the alcoholic fermentation is not done yet and the wine still has residual sugars.

The universalization in wine production has been restricting the imprint of terroir in regional wines, resulting in loss of typicity. Microbes are the main driving force in wine production, conducting fermentation and originating a myriad of metabolites that underly wine aroma. Grape berries harbor an ecological niche composed of filamentous fungi, yeasts and bacteria, which are influenced by the ripening stage, cultivar and region. The research project GrapeMicrobiota gathers a consortium from University of Zaragoza, University of Minho and University of Tours and aims at the isolation of native yeast strains from berries of the wine region Douro, UNESCO World Heritage, towards the production of wines that stand out in the market for their authenticity and for reflecting their region of origin in their aroma.

For sustainable viticulture, the substitution of chemical inputs with biocontrol products has become one of the most considered strategies. This strategy is based on elicitor-triggered immunity that requires a deep understanding of the molecular mechanisms involved in plant defense activation. Plant immune responses are triggered through the perception of conserved microbe-associated molecular patterns (MAMPs) which are recognized by pattern recognition receptors (PRRs) at the plasma membrane.