Application of nitrogen forms such as nitrate, urea, and amino acids effects on leaf and berry physiology and wine quality

During red wine fermentation, the extraction of phenolics compounds and sufficient oxygen provision are critical for wine quality [1,2]. In this trial, we aimed at evaluating the kinetics of phenolic extraction and dissolved oxygen during red wine fermentations using the airmixing system. Twenty lots of red grape musts were fermented in 300.000 L tanks, equipped with airmixing, using two injection regimes (i.e., high and low intensity, and high and low daily frequency). An oxygen analyzer was introduced into the tanks in order to record the concentration of dissolved oxygen over time.

A critical aspect of wine quality from a consumer perspective is the overall impression of wine flavour, which is formed by the interplay of volatile aroma compounds, their precursors, and taste and matrix components. Grapes contribute some potent aroma compounds, together with a large pool of non-volatile precursors (e.g. glycoconjugates and amino acid conjugates). Aroma precursors can break down through chemical hydrolysis reactions, or through the action of yeast or enzymes, significantly changing the aroma profile of a wine during winemaking and storage. In addition, glycoconjugates of monoterpenes, norisoprenoids and volatile phenols, together with sulfur-conjugates in wine, provide a reservoir of additional flavour through the in-mouth release of volatiles which may be perceived retro-nasally.

Powdery mildew, caused by Erysiphe necator, is a widespread disease that causes high economical losses in viticulture. The main strategy to control the disease is the recurrent application of sulphur based phytochemical compounds. However, in order to reduce their accumulation in the environment and promote the sustainability of the sector, the European Commission has applied restrictions to the number of pesticide treatments and the maximum quantity of fungicides to be applied in viticulture. Seaweeds, in particular macroalgae, are marine resources rich in sulphated polysaccharides with bio-protective potential for the plant, representing an environmentally-friendly alternative approach for sustainable wine production.

The designations of origin of the Loire Valley wine have been recognized according to customs and notoriety established over the centuries since the Middle Ages. There are four main production basins going up the Loire, from Nantes to the Sancerrois region: Nantes, Anjou-Saumur, Touraine and the vineyards of the Centre. In each of these basins, there is a wide range of appellations of origin which has been established according to a logic which may not seem obvious to the uninformed.

Over the next 25 years, the Intergovernmental Panel on Climate Change (IPCC 2013) predicts a ~20% increase in atmospheric carbon dioxide (CO2) concentration compared to the current level. Concurrently, temperatures are steadily rising. Grapevines, known for their climate sensitivity, will show changes in phenology, physiological processes and grape compositions in response. Investigating eco-physiological processes provides insights into the response of field-grown grapevines to elevated CO2 conditions. A Free Air Carbon Dioxide Enrichment (FACE) facility was established in the Rheingau region of Germany. Two grapevine varieties (Vitis vinifera L., cvs. Riesling and Cabernet Sauvignon) were planted, with the VineyardFACE comprising three rings with ambient atmospheric CO2 (approx. 400 – 420 ppm from 2014 to 2023, aCO2) and three rings with elevated CO2 concentration (+20% to ambient; eCO2).