Characterization of spoilage yeasts from Malbec grapes from San Rafael wine region (Argentina)

GARAU, JULIANA; MERÍN, MARÍA GABRIELA; MARTÍN, MARÍA CAROLINA; SEVILLANO, MARÍA EUGENIA; MORATA, VILMA INÉS

Logroño, La Rioja

Congreso; II International Congress on Grapevine and Wine Science; 2023

Instituto de Ciencias de la Vid y el Vino (ICVV)

The yeast ecosystem in grape musts is quite broad and depends on the region and the health of thegrapes. Within this, there are yeasts that can generate fermentative deviations or cause defects in the wine. Itis very important to address this issue because there are significant economic losses in the wine industry whenthe fermentation process or the organoleptic characteristics of the wine are negatively affected, even moretoday since climate change has a marked effect on the composition of this ecosystem. The aim of this work isto characterize the behavior regarding detrimental oenological features of potential spoilage yeasts isolatedfrom viticultural environments. Therefore, 36 non-Saccharomyces yeasts belonging to 9 species previouslyisolated from wine grapes cv. Malbec from districts of the winemaking region DO San Rafael (Mendoza,Argentina) were evaluated for their ability to produce acetic acid in calcium carbonate medium, hydrogensulfide (H2S) in BIGGY agar medium and undesirable aromas by a sensory evaluation after incubation inpasteurized grape juice with p-coumaric acid. In general, Pichia kudriavzevii strains were the larger producersof aroma defects, different from “Brett”, and H2S, but there was no sign of acid production. Strains of Hanseniaspora uvarum and Hanseniaspora guilliermondii produced unpleasant aromas, high acetic acid andlow values of H2S production. Other strains that showed interesting results were Zygosaccharomyces bailii and Hanseniaspora vineae; they were H2S producers and acidogenic, however they did not produce significantdefects in the grape must screening test. There are some strains that could be consider as possible winespoilage yeasts but deeper studies need to be done. It is important to study them in order to know the mainspecies responsible for the more significant damage in oenology with the purpose of controlling them.