Caracterização de leveduras isoladas do mosto de uvas Cabernet Franc da região de Bento Gonçalves - RS

Abstract

The elaboration of a good wine goes far beyond of terroir. It strongly depends upon the grape quality used and on the vinification process. Therefore, it is important to use a proper yeast for vinification. The autochthonous yeasts belonging a local microflora play an important role in this process, since they are more adapted to to the local substrate, and can enhance the aroma, the complexity and the typicity of the wine. This work aimed to characterize the yeasts of T84 series, which were collected from of grapes must of Cabernet Franc of Bento Goncalves region during the tumultuous phase of vinification. All strains have been assessed for fermentation performance, H2S production, killer skill and sensibility to the have presented similar fermentation skill compared to K1 and 1VVT standard strains and 20 out of the 49 strains did not produce H2S. The strains 117T84 and 154T84 have presented Killer factor with respect to Saccharomyces cerevisiae 26B84 strains and according to the sensibility test, 29 were sensitive to two Killer strain and just three yeasts did not show any sensibility to the Killer standard strain. The strain 144T84 presented neutral phenotype, because the cells neither kill the sensitive strains nor are killed by the killer yeasts. The 117T84 strain was identified by PCR/RFLP since it had shown atypical behavior. The identification was confirmed as Saccharomyces cerevisiae, as previously identified. The results show that the strains of Saccharomyces cerevisiae 117T84 and 154T84 are killer, do not form H2S and the strain 117T84 presents a mor expressive killer activity. The strain 144T84 was identified as Meyerozyma guilliermondii and has neutral phenotype. The strains 117T84 and 154T84 present an adequate enological potential to be used for wine production.