Impact of pre-fermentative maceration and yeast strain along with glutathione and SO2 additions on the aroma of Vitis vinifera L. Pošip wine and its evaluation during bottle aging

- Positive correlation between pre-fermentation maceration and varietal aroma compounds.
- Positive correlation between indigenous yeast strain and esters.
- Signficant decrease in concentrations of aroma compounds during aging.
- Combination of sulfur dioxide with glutathione has the most protective antioxidant effect.

The aim of the research was characterization and improvement of aroma of white wine Vitis vinifera L. Pošip by application of several enological practices, either individually or in combinations. The effect of pre-fermentative maceration, indigenous yeast strain and antioxidant additions (higher sulfur dioxide and glutathione) was examined, and compared to conventional white wine production: reductive pressing, commercial yeast strain and typical doses of free sulfur dioxide (35 mg/L). The most significant aroma contributors were esters and higher alcohols (fermentation aroma), as well as varietal aroma compounds such as linalool, β-damascenone and thiols (3SH and 3SHA). Furthermore, results showed that pre-fermentative maceration affected the higher concentrations of several aroma compounds, primarily those important for varietal character of wines: terpenes, norisoprenoids and varietal thiols. Fermentation by indigenous yeasts resulted in higher concentrations of different compounds, especially of i-amyl acetate which contributes to desirable fruity, banana-like odors. Furthermore, during 12 months' aging, most of the aroma compounds significantly decreased, but in wines bottled with antioxidant additions (higher free sulfur dioxide, glutathione and their combination) their slower decrease was observed. The most notable protective effect was observed using the combination of higher free sulfur dioxide (50 mg/L) with glutathione (20 mg/L).