The influence of different yeast strains and yeast nutrients on the aroma of krstach and zhizhak wines

Krstach and Zhizhak are autochthonous grape varieties grown in Montenegro. Although international varieties are more popular, the autochthonous varieties are very important, especially for countries developing tourism. The fermentation aromas produced during alcoholic fermentation contribute significantly to wine quality. The effects of yeasts (Saccharomyces cerevisiae and Saccharomyces bayanus) and yeast nutrients (Fermaid E and Fermaid O) on aromatic compounds in wines were investigated. Using GC/FID-MS analysis, aroma compounds in Krstach and Zhizhak wines were characterized and quantified. Wines produced with the addition of yeast and yeast nutrients had mostly lower total alcohol content than wines obtained by spontaneous fermentation of Krstach and Zhizhak varieties. The results of this study showed that the concentration of compounds depends on the yeast strains. The yeast S. cerevisiae (ICV) provided a higher content of higher alcohols, while S. bayanus produced a higher concentration of esters and (medium chain) fatty acids. Total ester content ranged from 3.34 to 11.97 mg/l for Krstach wines and 8.51 to 13.68 mg/l for Zhizhak wines. Among all wines, Krstach and Zhazhak wines produced with S. bayanus and Fermaid E addition had the highest concentration of total esters. The yeast nutrients Fermaid E and O emphasized different characteristics of the yeasts. They had a statistically significant effect on the content of ethyl and acetate esters. The highest overall scores were obtained for ICVE and BayE Krstach wines (18.1 out of 20 points) and Zhazhak ICVE wine (18.2 out of 20 points). (author)