Native yeast selection to improve red wine aroma by fermentation at low temperature

MASSERA A.; STURM M.E.; SARI S.; ROJO M.C; JOFRÉ V.; COMBINA M.

París

Simposio; Yeasts for health and biotechnologies; 2009

Instituto Pasteur

A technological advance in winemaking has been the microbiological control of the fermentative process by using selected lSaccharomyces cerevisiae starters. The use of autochthonous wine yeasts selected from each viticultural region is a widespread practice. These yeasts are better acclimated to local conditions of wine production and can more easily dominate on the natural flora. The aroma and flavor of wine are among the main characteristics that determine its quality and value. The nature and amount of volatile compounds in wine depend on multiple factors, such as the temperature of fermentation and the yeast strain. Low temperatures are used in white and rosé wine fermentations to enhance and retain flavor volatiles but it is not commonly used in red wine fermentation. The aim of this work was select autochthonous S. cerevisiae strains for their aptitude to carry out red must fermentation at 15ºC and improve the aroma.S. cerevisiae indigenous strains previously selected for their enological and phenotypic characteristics determined in the laboratory were evaluated in microvinifications (5L). The strains whose wines had the best analytical and sensory characteristic were evaluated in red must fermentations at pre-industrial scale (80 L).S. cerevisiae strains molecular identity was determined after all fermentations. Conventional parameters of wines were measured and sensory analyses were performed. S. cerevisiae population was above 90 %. In microvinifications, UBA-21 was unable to complete the fermentation while all native yeasts produce less volatile acidity that the control yeasts. Ma B-2C, Ma E-1C and Bo-1C produced wines with better chemical and organoleptic characteristics so these strains were evaluated in the next stage. At pilot scale, Ma B-2C and Bo-1C produced less volatile acidity. GC/MS and sensory analyses were useful to differentiate between the strains. Ma B-2C wines have more terpenes while Bo-1C wines have a lot of esters and high alcohols, and were related with banana and floral aromas. Ma B-2C and Bo-1C were selected because their wines have desired chemical and organoleptic characteristic without off-flavours. Wine quality is related with the process and the yeast strain used. Therefore, selecting the appropriate strain for each type of fermentation is a very important strategy to ensure good fermentation and improve the wine flavour.