Understanding and managing wine production from different terroirs

The chemical mechanisms involved in oxidation/reduction potential of wine during winemaking and aging are affecting its color, aroma and taste. Chemical oxidation is one of the major causes of development of off-flavors during ageing1. Thus, the chemical changes in wine during storage should be controlled to ensure the sensory quality of the product and avoid consumer rejection that will compromise the economic value of the product. The 1-hydroxyethyl radical has been recognized as the key radical intermediate in the oxidative reactions in wine2. Based on the kinetic study of POBN-1-hydroxyethyl spin adduct formation in wines initiated via the Fenton reaction, a novel tool was recently developed in our laboratory to quantify the resistance of wines against oxidation3.

Rootstocks not only provide tolerance to Phylloxera, but also ensure the supply of water and mineral nutrients to the whole plant. Rootstocks are an important way of adapting to environmental conditions while conserving the typical features of scion varieties. We can exploit the large diversity of rootstocks used worldwide to aid this adaptation. The aim of this study was to characterise rootstock regulation of scion mineral status and its relation with scion development.

L’objectif de cette recherche est le zonage climatique des périodes viticoles de l’année dans la Vallée du São Francisco, région brésilienne productrice de vins située en climat tropical semi-aride. Dans cette région, la production peut être échelonnée sur tous les mois de l’année.

The application of different winemaking techniques helps to modify the basic parameters, phenolic profile, and aroma components influencing the final wine quality. In particular, pre-fermentative processes aim to increase the extraction and preservation of grape native compounds. Among them, cold liquid stabulation (macération sur bourbes) consists in maintaining the grape juice on its lees, in suspended condition at low temperature (0-8 °C) for a variable time (generally from 7 to 21 days). The aim of this work is to apply the cold liquid stabulation on two Italian white grape varieties, Arneis and Cortese, to evaluate the impact on basic parameters, color, polyphenolic compounds (TPI), antioxidant power (DPPH), total polysaccharides, and free and glycosylated volatile compounds (GC-MS analysis) during and after the process.

Samples from 3 wine types were treated with a cationic exchange resin (7 lots) and stored for 8 years (47 samples). Forty-seven parameters were determined, including (1) important substrates with impact in white wine oxidation and (2) markers of oxidation. From group 1, sugars, elements, phenolic compounds, α-dicarbonyls and SO2 and from group 2, browning (A420), acetaldehyde, alkanals, furanic compounds were quantified.