The Use of Hanseniaspora opuntiae to Improve 'Sideritis' Wine Quality, a Late-Ripening Greek Grape Variety.

In view of climate change and the increasingly antagonistic wine market, the exploitation of native genetic resources is revisited in relation to sustainable wine production. 'Sideritis' is a late-ripening Greek grape variety, which is quite promising for counteracting wine quality issues associated with the annual temperature rise. The aim of this study was to improve the quality and to enhance the aroma of 'Sideritis' wine through the use of native yeasts. To improve vinification, Hanseniaspora opuntiae L1 was used along with Saccharomyces cerevisiae W7 in mixed fermentations (SQ). The addition of H. οpuntiae significantly altered the chemical profile of the wine compared to the single-inoculated fermentations with W7 (IS). H. opuntiae increased all the acetate esters, except for hexyl acetate and (Z)-3-hexen-1-ol acetate. The concentration of 2-phenylethyl acetate, which imparts flowery and sweet notes, exhibited a 2.6-fold increase in SQ as compared to IS wines. SQ also showed higher levels in several ethyl esters, including ethyl butyrate, ethyl heptanoate and ethyl 7-octenoate, which are associated with fruity notes compared to IS. H. opuntiae produced citronellol, a terpene associated with rose and green notes, and increased the overall acceptance of the wine. Present results are thus quite promising for improving 'Sideritis' wine quality towards a sustainable wine production in Greece in view of global warming.

The effect of vine variety and vintage on wine yeast community structure of grapes and ferments.

AIMS: The yeast community structure associated with grapes is an essential part of the wine-growing chain with a significant effect on wine quality. The aim of the present study was to evaluate the effect of the varietal factor on the yeast community assembly on grapes and during must fermentation. METHODS AND RESULTS: We analysed the wine yeast populations associated with four different grape varieties from the Greek national collection vineyard of Lykovryssi. The vintage effect was also considered by sampling the grapes for two consecutive years. Fourteen yeast species were recovered and genotyped to distinct subpopulations. A relatively stable yeast community structure was detected across vintages, with Hanseniaspora guilliermondii being the core species of the vineyard under study. The detected species subpopulations shared a relatively high genetic similarity with several genotypes persisting across vintages. CONCLUSIONS: It was shown that different grape cultivars were associated with distinct yeast communities, pointing to their possible implication on wine chemical diversity. SIGNIFICANCE AND IMPACT OF THE STUDY: Present findings show that the varietal factor is an important sharpener of the vineyard-associated wine yeast community, which may interfere with the organoleptic profile of the resulting wines.