EFFECT OF OENOLOGICAL NON-Saccharomyces YEASTS ON MALOLACTIC FERMENTATION AND Oenococcus oeni

Entity: Universitat Rovira i Virgili (URV)

Confidenciality: No

Education area(s): Begudes Fermentades

Title in different languages: EFFECT OF OENOLOGICAL NON-Saccharomyces YEASTS ON MALOLACTIC FERMENTATION AND Oenococcus oeni

Abstract: ABSTRACT In the last few years it has increased the interest on the use of non-Saccharomyces yeasts in winemaking. Generally, these yeasts are inoculated to start the alcoholic fermentation (AF) of must and later, Saccharomyces cerevisiae is inoculated to finish the process. This type of sequential inoculation with non-Saccharomyces yeasts it has been linked with the organoleptic improvement of some wines. Some species have been reported as beneficial, such as Torulaspora delbrueckii, Metschnikowia pulcherrima, Hanseniaspora uvarum, H. vineae and Starmerella bacillaris (syn. Candida zemplinina), etc. In particular, Torulaspora delbrueckii, Metschnikowia pulcherrima are available as starter cultures in winemaking. Despite the increasing interest in non-Saccharomyces yeasts, there are not many works in which are evaluated the possible effects of these yeasts upon the malolactic fermentation (MLF). Some strains produce other changes that could directly affect to the lactic acid bacteria Oenococcus oeni growth, the main agent of MLF. The increase of succinic acid and/or the consumption of L-malic acid that has been reported in some non-Saccharomyces could act as MLF inhibitors. What is more, the ethanol content and SO2 decrease, could positively affect the adaptation of O. oeni to wine. For this purpose, this present work considers the study of the use of non- Saccharomyces upon O. oeni and MLF. There were evaluated experimental mixed fermentations with the species H. vineae, H. uvarum, M. pulcherrima with S. cerevisiae, as well as a control fermentation with S. cerevisiae. After the chemical characterization of the obtained wines, two strains of O. oeni were inoculated; PSU-1 and 1PW13, and it was studied their behaviour in those wines. The obtained wines after the AF by the different mixes of the studied non- Saccharomyces did not show very diverse chemical composition in regards to the evaluated parameters. However, the inoculated O. oeni strains, could only undergo the MLF in the wines obtained by the AF of H. uvarum and M. pulcherrima with S. cerevisiae. In the other cases, the MLF did not conclude. What is more, in this study it was not observed that the increase in succinic acid concentration had a direct inhibitory effect upon the MLF, as it is described in literature. The results will allow determining the main effects of the use of non-Saccharomyces yeasts upon O. oeni and will be employed as yeast-bacteria selection criteria. Key words: non-Saccharomyces, Oenococcus oeni, malolactic fermentation, interactions

Subject: Vinicultura

Academic year: 2015-2016

Language: Anglès

Work's public defense date: 2016-06-22

Subject areas: Enology

Student: BALMASEDA RUBINA, AITOR

Work's codirector: CRISTINA REGUANT, ALBERT BORDONS

Department: Bioquímica i Biotecnologia

Creation date in repository: 2016-09-07

TFM credits: 15

Keywords: Non-Saccharomyces, Oenococcus oeni, malolactic fermentation, interactions

Title in original language: EFFECT OF OENOLOGICAL NON-Saccharomyces YEASTS ON MALOLACTIC FERMENTATION AND Oenococcus oeni

Access Rights: info:eu-repo/semantics/openAccess

Project director: BAUTISTA GALLEGO, JOAQUÍN