Changes in phenolic compounds, chromatic characteristics, acetaldehyde, and protein-reactive tannins associated with oxidative aging were studied in Sangiovese wines with varied tannin T/anthocyanin A ratios. For this purpose, three Sangiovese vineyards located in Tuscany were considered in the 2016 vintage. To obtain wines with different T/A ratios, two red wines were produced from each vinification batch: a free run juice with a lower T/A ratio and a marc pressed wine with a higher T/A ratio. An overall of six wines with T/A ratios ranging between 5 and 23 were produced. An oxidation treatment (four saturation cycles) was applied to each wine. Average and initial oxygen consumption rates (OCR) were positively correlated to VRF/mA (vanilline reactive flavans/monomeric anthocyanins) and T/A ratios while OCRs were negatively related to the wine content in monomeric and total anthocyanins. The higher the A content was, the greater the loss of total and free anthocyanins. A significant lower production of polymeric pigments was detected in all pressed wines with respect to the correspondant free run one. A gradual decrease of tannin reactivity toward saliva proteins after the application of oxygen saturation cycles was detected. The results obtained in this experiment indicate that VRF/mA and T/A ratios are among the fundamental parameters to evaluate before choosing the antioxidant protection to be used and the right oxidation level to apply for a longer shelf-life of red wine.

The polyphenol extraction and evolution during a traditional 14-day fermentation of the Aglianico red grape, a variety widely cultivated across Southern Italy, was for the first time investigated, with the purpose of optimizing the phenolic profile in finished wines. Anthocyanins, BSA-reactive tannins, iron-reactive phenols, and vanillin-reactive flavans (VRFs) were analyzed in the free-run must, pressed pomace liquid, and in pomace extracts at different maceration times. Experimental evidence suggested that, instead of the typical 14-day maceration of Aglianico grapes, it is recommendable to choose an 11-day maceration in order to prevent the over-extraction of polyphenols that may detrimentally affect the sensory characteristics of wines. In fact, Aglianico wines, if not properly produced, can be affected by excessive astringency due to its high tannin contents. The findings of the present study can provide insightful knowledge to all the winemakers dealing with grape varieties characterized by high quantities of tannins. Also, an earlier racking would supply grape pomaces extremely rich in valuable phenolic compounds to be extracted and reused in several industrial segments in the frame of circular bioeconomy.