Direct NMR evidence for the dissociation of sulfur-dioxide-bound acetaldehyde under acidic conditions: Impact on wines oxidative stability

Most of the rootstocks used in viticulture today are partly resistant against grape phylloxera (Daktulosphaira vitifoliae Fitch) and host phylloxera on the root system without conspicuous negative impacts on fruit production).

The availability of water for irrigation is usually greater at the beginning of spring than in the following months, until the end of summer, in most regions of Spain.

Koshu is one of the indigenous grape variety that has been grown in Japan for more than one thousand years. Recent research showed that it has 70% of Vitis vinifera genes. In 2010, the Koshu variety was included in ‘International List of Vine and Varieties and their Synonyms’ managed by the ‘International Organisation of Vine and Wine’ and has further fueled its popularity in Japan. It is the most cultivated variety for winemaking in Japan.
Koshu berries have light purple skins. The variety is mainly used to produce white wines such as an aromatic wine and a wine produced by sur lie method although various styles are produced.

Increasing concentrations of greenhouse gases (GHGs) in the atmosphere due to human activities are leading to a rise in the average temperature of the atmosphere. among the scenarios established by the un’s intergovernmental panel on climate change (IPCC), only two enable us to achieve the minimum objective of the paris agreements signed at cop 21 in 2015: staying below +2°c after 2050. both scenarios forecast a rapid reduction in GHG emissions as early as 2025, thanks to strong international cooperation, the priority given to sustainable development and responsible consumer choices.

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.