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TITLE:
Selecció de soques de lachancea thermotolerans per a la reducció del grau alchòlic dels vins - TFG:4236
Handle: https://hdl.handle.net/20.500.11797/TFG4236

Student:Celma Barceló, Judith
Language:cat
Title in original language:Selecció de soques de lachancea thermotolerans per a la reducció del grau alchòlic dels vins
Title in different languages:selection of strains of lachancea thermotolerans for the reduction of the alcoholic grade of the wines
Keywords:Lachancea thermotolerans, Saccharomyces cerevisiae, lactic acid, ethanol, individual fermentation, sequential fermentation.
Subject:Enologia
Abstract:In the viticulture and viniculture sector, climate change is one of the elements that has considerably affected the zones where grapes are grown. Due to the temperature increase, the grapes that are obtained are riper and with a higher sugar quantity and, at the end, we obtain a final product with a high ethanol concentration. Fundamentally, the worldwide health problems and the people’s demands of healthier products forces us to look for alternatives more accessible to the public that retain the sensorial and organoleptic properties of the wine, even if the alcoholic degree is lower. This work is focused on the research of a yeast that can diminish the alcohol content in a wine, while preserving the taste, acidity, aroma, and other organoleptic parameters of the wine, using different strains of the Lachancea thermotolerans species. This species is able to use part of the sugar of the grape juice to produce lactic acid, thus reducing the ethanol content and regulating the acidity. To accomplish this work, different strains of L. thermotolerans have been studied, using a commercial strain of Saccharomyces cerevisiae as a control . First, individual fermentations were performed to evaluate the characteristics of the different strains of L. thermotolerans, and then, those that had better results individually were tested in sequential fermentations with a S. cerevisiae strain. For monitoring the imposition of the inoculated yeasts, as well as possible contaminations, yeasts were identified, at species level, with the technique PCR-RFLP of the DNAr 5,8S-ITS region. After revising the individual fermentations, the strains Lt2 and LtCW8 were chosen to continue the study, since both strains showed the highest lactic acid concentration at the end of the fermentations, as well as the highest decrease on the alcoholic degree in relation with the other strains that were studied. Therefore, sequential fermentations were carried out with these strains and the S. cerevisiae strain QA23, obtaining positive results in both cases. After these preliminary data, more testing should be done to assess if these strains could be used to reduce the alcoholic degree at commercial level.
Project director:Torija Martínez, M. Jesús
Department:Bioquímica i Biotecnologia
Education area(s):Enologia
Entity:Universitat Rovira i Virgili (URV)
Creation date in repository:2021-11-25
Work's public defense date:2021-09-02
Academic year:2020-2021
Confidenciality:No
Subject areas:Enology
Access rights:info:eu-repo/semantics/openAccess
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