Effect of inoculation strategy of non-Saccharomyces yeasts on malolactic fermentation and Oenococcus oeni

Identifier:  TFM:325

Handle: https://hdl.handle.net/20.500.11797/TFM325

Authors:  Martín Garcia, Alba

Abstract:
In recent years, the use of non-Saccharomyces yeast has increased to obtain wines with a different organoleptic profile. In general terms, these yeasts are inoculated to begin alcoholic fermentation (AF) and later Saccharomyces cerevisiae is inoculated to finish the process. This sequential inoculation leads to wine quality enhancement. However, non-Saccharomyces can affect Oenococcus oeni and malolactic fermentation (MLF). In the present work, there were evaluated two non-Saccharomyces strains, Torulaspora delbrueckii (Biodiva) and Metschnikowia pulcherrima (Flavia), through mixed and sequential fermentations with S. cerevisiae (QA23). Sequential fermentations were performed with different times of inoculation of S. cerevisiae (24h, 48h and 72h). A fermentation with S. cerevisiae as a single starter was also performed as a control. Next, FML was performed in all wines inoculating O. oeni (PSU-1). Finally, wines obtained after AF and MLF were characterized. The results obtained from mixed fermentations did not show differences compared to S. cerevisiae control fermentation. Nevertheless, significant differences were observed in sequential fermentations regarding, mainly, acetic acid, L-malic acid and succinic acid content. Those differences were highlighted in fermentations carried out with T. delbrueckii. However, none of the non-Saccharomyces fermentations improved MLF speed.