Enhancing the stability of a red organic wine through hydroxytyrosol supplementation at bottling: A time-dependent analysis

Abstract

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.