Effects of different vinification technologies on physical and chemical characteristics of Sauvignon blanc wines

In order to investigate the effects of cryomaceration and reductive vinification on chemical and physical indices and on antioxidant compounds of Sauvignon blanc wines, four wine-making procedures were applied: traditional white vinification, skin cryomaceration, vinification in a reductive environment, and the combination of the last two procedures. Significant differences were highlighted by both conventional analyses and NMR spectroscopy. The strongest changes were highlighted for organic acid concentrations (tartaric, in particular) and phenolic content. Cryomaceration caused a strong precipitation of tartaric acid that could be desired in the cases in which grapes must be harvested regardless high acidity values. Furthermore, the application of cryomaceration protected the flavans reactive with vanillin from the action of oxidative enzymes. The vinification in a reductive environment, alone or combined with a cryomaceration step, gave wines with the highest dry extracts and caused a greater extraction of phenolic compounds from skins if compared to the traditional winemaking or to the sole cryomaceration, due to the SO2 solubilisation action. The application of PCA to conventional indices, antioxidant content, and NMR signals highlighted the possibility to deeply modify the grape oenological expression through the application of the investigated wine-making procedures.