Interaction between the enzymes of central carbon metabolism and anthocyanin biosynthesis during grape berry development

Among nitrogen compounds included in white wines, the peptide fraction is certainly the least studied, however this fraction is quantitatively the most important (Feuillat, 1974). Existing studies concern the fraction below 1 kDa and only for white and sparkling wines (Bartolomé et al, 1997, Desportes et al 2000). In this report, we have developed methods to isolate peptides from reference white wines. Then, we have applied this methodology with bitter wine to answer a research question: is there a relation between peptides and the bitterness of white wine as for some cheese for example (Furtado, 1984)?

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.

Grape anthocyanin content and composition could affect the quality and the production strategies of red wines. Differences in the pigment composition modify the color properties in terms of hue, extractability and stability. Thus, for the production of a highly qualitative wine such as “Amarone”, variations in the pigment composition are not negligible. The aim of this work was the investigation of the anthocyanin profile changes during ripening in Corvina grapes, the main cultivar for the “Amarone” production. The experiment took place in 2015, in two vineyards located in Valpollicella (Italy).

Leaf removal in the bunch zone is a common viticultural practice with several objectives, yet it has been difficult to conclusively link the physiological mechanism(s) and metabolic berry impact to this widely practiced treatment. We used a field-omics approach1 in a Sauvignon blanc high altitude model vineyard, showing that the early leaf removal in the bunch zone caused quantifiable and stable responses (over years) in the microclimate where the main perturbation was increased exposure. We provide an explanation for how leaf removal leads to the shifts in grape metabolites typically linked to this treatment and confirm anecdotal evidence and previous reports that leaf removal treatment at an early stage of berry development affects “quality-associated” metabolites (monoterpenes and norisoprenoids).

This study investigates how the sensory profile of Pinot Blanc is affected from different maceration and pressing techniques. Grapes were sourced from four vineyards in the village Tramin in South Tyrol. For the experiment 200 kg of grapes from each vineyard site were hand picked the day before harvest for the commercial winery took place. Grapes were stored over night at 4°C, homogenized and processed in the experimental winery at Laimburg research centre the day after harvest. Four different pressing techniques were applied in duplicates of 100kg each.