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

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

Logroño, La Rioja

Congreso; II International Congress on Grapevine and Wine Sciences (2ICGWS); 2023

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

The yeast ecosystem in grape musts is quite broad and depends on the region and the health of the grapes. Within this, there are yeasts that can generate fermentative deviations and/or cause defects in the wine. It is very important to address this issue because there are significant economic losses in the wine industry when the fermentation process and/or the organoleptic characteristics of the wine are negatively affected, even more today since climate change has a marked effect on the composition of this ecosystem. The aim of this work is to characterize the behavior regarding detrimental oenological features of potential spoilage yeasts isolated from viticultural environments. Therefore, 36 non-Saccharomyces yeasts belonging to 9 species previously isolated from wine grapes cv. Malbec from 4 districts of the winemaking region DO San Rafael (Mendoza, Argentina) were evaluated for their ability to produce acetic acid in calcium carbonate medium, hydrogen sulfide (H2S) in BIGGY agar medium and undesirable aromas by a sensory evaluation after incubation in pasteurized grape juice with p-coumaric acid. In general, Pichia kudriavzevii strains were the larger producers of 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 and low 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 significant defects in the grape must screening test. There are some strains that could be consider as possible wine spoilage yeasts but deeper studies need to be done. It is important to study them in order to know the main species responsible for the more significant damage in oenology with the purpose of controlling them.