Neural networks and ft-ir spectroscopy for the discrimination of single varietal and blended wines. A preliminary study.

Of biocontrol products and resistant grape varieties, synthetic pesticides are still widely used to control fungal diseases and protect vines from potential damage caused by pests. The use of pesticides is strictly regulated, and their use can sometimes lead to transfer from the grapes to the must and then into the wine. The study of pesticide residues in grapes and wines is commonly carried out by wine producers in order, among other things, to optimize treatment routes, check that products comply with regulations, and ultimately guarantee the food safety of the wine.

Oenological tannins are products extracted from various botanical sources, such as mimosa,
acacia, oak gall, quebracho, chestnut and tara. The polyphenolic component is obtained through a solid-liquid extraction also using specific solvents, then removed by evaporation or freeze-drying. Tannins are employed in two phases of winemaking, during the pre-fermentative phase or during fining with different purposes such as modulate antioxidant activity, colour stabilization, bacteriostatic activity, protein stabilization and modulation of sensory properties. To date, the current regulatory framework is not very clear. In fact, the Codex Alimentarius classifies commercial tannins as “food additives” but also as
“processing aids”. The main distinction is that “additives” have a technological function in the final food, whereas “processing aids” do not. In this sense, oenological tannins, despite the technological treatments, could contain aromatic compounds of the botanical species they belong to and release them to the wine.

Wine is one of the most consumed and appreciated beverages in the world. Due to the growing attention paid to consumer health, there is a continuous search for sustainable alternatives to common additives (such as sulfur dioxide) used to preserve wine. An example is represented by chitosan, the main derivative of chitin, approved for the treatment of must and wine since 2009 by the “international organization of vine and wine” (OIV/OENO 338a/2009) and by the european commission (EC Reg. No. 606/2009).

Oenococcus oeni is the main Lactic Acid Bacteria responsible for malolactic fermentation, converting malic acid into lactic acid and carbon dioxide in wines. Following the alcoholic fermentation, this second fermentation ensures a deacidification and remains essential for the release of aromatic notes and the improvement of microbial stability in many wines. Nevertheless, wine is a harsh environment for microbial growth, especially because of its low pH (between 2.9 and 3.6 depending on the type of wine) and nutrient deficiency. In order to maintain homeostasis and ensure viability, O. oeni possesses different cellular mechanisms including organic acid metabolisms which represent also the major pathway to synthetize energy in wine.

Grapevine phenology is advancing with increased temperatures associated with climate change. This may result in higher fruit sugar concentrations at harvest and/or earlier compressed harvests and changes in the synchrony of sugar with other fruit metabolites. One adaptation strategy that growers may use to maintain typicity of wine style is to change cultivars. This approach may enable fruit