Banques de données biologiques annuelles par terroir et optimisation des itinéraires culturaux

Tyrosol (TYR) and hydroxytyrosol (HYT) are bioactive phenols present in olive oil and wine, basic elements of the Mediterranean diet. TYR is reported in the literature for its interesting antioxidant, cardioprotective and anti-inflammatory properties. In wine, its concentration can reach values as high as about 40 mg/L
[Pour Nikfardjam et al. 2007] but, more frequently, this phenol – derived from yeast metabolism of tyrosine during fermentation – is present at lower levels, generally higher in red wines compared to whites. HYT was measured for the first time by Di Tommaso et al. [1998] in Italian wines – with maximum values of 4.20 mg/L and 1.92 mg/L for red and white wines, respectively – while definitely lower concentrations have been found later in Greek samples.

Valpolicella is a famous wine producing region in the province of Verona owing its fame above all to the production of two Protected Designation of Origins (PDOs) withered wines: Amarone and Recioto. In recent years, however, the wineries have been interested in the enhancement and qualitative increase of another PDO, Valpolicella Superiore. All the Valpolicella PDOs wines are produced with a unique grape blend, mainly Corvina, Corvinone, Rondinella and a range of other minor varieties.From 2019 Valpolicella product regulation has changed the grape proportion of the blend allowing new composition parameters of wines. For this reason, studying the volatile chemical profiles to support wine makers in the effort to produce high quality wines represents a field of great interest.

The presence of unstable proteins in wines can affect their stability and clarity. Before bottling, winemakers need to be sure that the wine is stable. A large number of stability tests have been proposed, usually based on heating a sample with a specific time-temperature couple. In practice, none is effective to accurately assess the risk of instability. Moreover, the interpretation of the results of these tests changes according to the region.

Vineyard nutrient management is crucial for reaching production-specific quality standards, yet timely evaluation of nutrient status remains challenging. The existing sampling protocol of collecting vine tissue (leaves and/or petioles) at bloom or veraison is time-consuming. Additionally, this sampling practice is too late for in-season fertilizer applications (e.g. N is applied well before bloom). Therefore alternative early-season protocols are necessary to predict the vine nutrient demand for the upcoming season. The main goals of this project are to 1) optimize existing tissue sampling protocols; 2) determine the amount of nutrients removed at the end of the growing season.

Sunburn results from a combination of excessive photosynthetically active radiation (PAR) and UV radiation and temperature that can be exacerbated by other stress factors such as water deficit. Sunburn is a physiological disorder that affects the visual and organoleptic properties of grapes. The appearance of brown and necrotic spots severely affects the commercial value of the fruit, and in extreme cases, significantly decreases yield. This damage occurs with some frequency in sensitive varieties such as Graciano.