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The effect of the addition of hydroxytyrosol (HT) in a red organic wine (Sangiovese 85 % and Cabernet Sauvignon 15 %) was evaluated. After six months of storage in a concrete tank, the wines were spiked with HT in three different amounts (30, 60, 120 mg/750 mL in wine) and compared with a control bottled wine (no HT addition). The bottled wines were stored at room temperature and were opened after a period of one, three, six, nine and twelve months to perform chemical and sensory analyses (T1, T3, T6, T9, and T12, respectively). Storage time was the factor that most influenced all wines parameters with respect to the different treatments. However, wine added with 60 and 120 mg/750 mL HT had a lower amount of acetic acid than the control at T3 and T6. At T6, the measured HT was negatively correlated with acetic acid (R2 = 0.81), thus suggesting that HT preserved the wine from oxidation. Later, this trend was not confirmed. The content of HT spiked was stable over twelve months of bottle storage; only the endogenous HT, which is naturally present in wine, showed a decrease of 44 % after twelve months of bottle storage. Yellowness (b*) was higher in the 30 mg/750 mL at T9 compared to the other samples. Lightness (L*) showed a decrement of 11 %, while a* (redness) increased by 21 % from T1 to T12. After T6, the wine fortified with 120 mg/750 mL was preferred by the sensory panel; however, it was the only sample to be clustered by the panel at T9 and ''red fruits,'' ''spicy'', and ''astringency'' sensory attributes played an important role in this separation.

The sensory and chemical properties of ‘Pinot Blanc’ wine from South Tyrol were studied in relation to vineyard location and winemaking technique. Musts and wines were collected from a local producer. Wines made with the same control vinification but from different vineyards (Aldino 800, Montagna 450, and Klaus 550 m.a.s.l) were analyzed. Then wines from grapes of the same vineyard but made with different vinifications (grape freezing and co-inoculation of yeast with malolactic bacteria, both compared against controls) were compared. The highest-altitude vineyard (cooler temperatures, increased UV radiation, and increased airflow) impacted positively the wine quality. The different vinifications produced differences at various storage times. Finally, sensory attributes predictors for the overall quality and related chemical variables were identified. As climate change pushes growers to increasingly high-altitude viticulture, if/when allowed by the environmental conditions, these results can contribute to understand which winemaking techniques are best in these more challenging conditions.

The present study investigates the presence of α-terpinyl ethyl ether in wine and gives insights on the chemical processes leading to its formation. The analytical determination of (S)-α-terpinyl ethyl ether and (R)-α-terpinyl ethyl ether enantiomers was obtained by enantioselective comprehensive two-dimensional gas chromatography. Applying the two isomers as variables in combination with closely related terpenes, an accurate classification model of wines for the grape variety was successfully applied to a representative set of single-variety wine samples. Although presenting relatively low absolute concentrations, α-terpinyl ethyl ether (along with α-terpineol) resulted to be an inevitable and irreversible degradation product of linalool. In fact, a conversion study from enantiomerically pure (R)-linalool showed a major loss of the initial chiral configuration, i.e. only a very small enantiomeric excess characterized the product. α-Terpineol itself was also confirmed to be a precursor of α-terpinyl ethyl ether, however this process showed a smaller conversion over two weeks than from linalool, and without losses of the initial chiral configuration. In the real samples, the concentration of α-terpinyl ethyl ether was found to be much lower than that of α-terpineol, regardless of the alcohol-to-water ratio. Finally, olfactory descriptors were qualitatively attributed to each α-terpinyl ethyl ether enantiomer.

A red wine that had aged in bottle for five years was treated with ultrasound (40 kHz) for 5 min and 30 min twice weekly and analysed after 3, 6, 9, and 12 months. Sensory analysis showed differences in overall quality at months 3 and 6, with the ultrasound-treated wines preferred. The ultrasound treatment did not decrease the free sulfur dioxide content. Differences in anthocyanins, polyphenols, and proanthocyanidins were clearest at month 9. In contrast, differences in the volatile profile were clearest at month 3. From a commercial point of view, the low-energy treatment (5 min) might be preferable given the lower costs. Ultrasound treatment was effective in enhancing the overall quality during the first 6 months of bottle storage in an aged red wine and did not increase the risk of oxidation or microbial spoilage. This work made it possible to fine-tune ultrasound treatment to maximise its positive effects.

The effects of a) pre-fermentative freezing of the grapes (- 20 °C for two weeks); b) inoculation of the grape must with Saccharomyces cerevisiae yeast, or co-inoculation with Saccharomyces cerevisiae yeast and Oenococcus oeni bacteria; c) vinification with or without fermentative maceration, and d) cold stabilization with or without bentonite treatment, were studied on the profile of oligomeric condensed tannins (proanthocyanidins, PAC) with non-cyclic or macrocyclic structures in wines made from Schiava cv., a red grape variety. The samples were evaluated just before inoculation and at the bottling of the wine. Commercial Schiava wines from two different producers stored at six and eighteen months were also studied for the effect of artificially introduced dissolved oxygen, and half of these bottles were subjected to periodic mechanical stress for one year, to see the effects on the PAC profile. Freezing of the grapes increased the extraction of all non-cyclic PAC in the must, whereas tetrameric, pentameric, and hexameric cyclic procyanidins (m/z 1153, m/z 1441, m/z 1729, respectively) were not affected; only a tetrameric cyclic prodelphinidin ( m/z 1169) showed a more similar trend to the non-cyclic PAC. In wines at bottling, cyclic procyanidins were higher in wines obtained by fermentative maceration (as well as most non-cyclic congeners); however, the significance of these differences depended on specific interactions between the factors. In contrast, no effect was found on the cyclic tetrameric prodelphinidin (m/z 1169). Bentonite treatment showed no significant effect on either oligomeric non-cyclic or cyclic PAC profiles. The addition of dissolved oxygen led to a significant decrease in non-cyclic trimeric and tetrameric PAC in the samples with respect to the control ones; however, the addition of dissolved oxygen did not influence the profile of the cyclic PAC. This study sheds new light on the substantial differences in the behaviour of the cyclic and non-cyclic oligomeric PAC in red wine in relation to the vinification process and in the bottle. Cyclic oligomeric PAC were more stable and less influenced by applied factors than linear PAC, again proving to be potential markers for the grape variety of wine.