nfluence of Timing of Oenococcus oeni Inoculation on the Sensory Characteristics of the Must Fermented by Yeasts Mixed Culture from Argentina Northwest

MENDOZA LUCÍA M.; FARÍAS MARTA E

San Diego, California

Congreso; 110th ASM General Meeting; 2010

American Society of Microbiology

Malolactic fermentation (MLF) is important in wine quality, increasing microbiological stability and enhancing the flavour. Oenococcus oeni is the most suitable species to conduct MLF. There is controversy about the convenience of MLF consecutive or simultaneous to alcoholic fermentation, specifically with regard to the wine composition. This work evaluated the differences in sensory characteristics of wines from Northwest Argentina inoculated simultaneously or sequentially with indigenous yeasts and lactic acid bacteria in microvinification conditions. Saccharomyces cerevisiae mc2 (high fermentative power) and Kloeckera apiculata mc1 (high contribution to wine taste), were single or mixed inoculated in Malbec grape must and O. oeni X2L was simultaneously or sequentially inoculated. The fermentation products were determined by enzymatic methods; aroma compounds by gas chromatography and sensory evaluation was carried out by 6 judges trained in wine tasting. Wines fermented by S. cerevisiae in pure or mixed cultures contained 13-14% of ethanol. However, the amount of esters was higher in fermentations conducted by yeasts mixed starter. Wines fermented by composite culture of yeasts and O. oeni simultaneously inoculated were not accepted by judges because their high levels of acetic acid as well as phenolic aroma. Although the wines obtained from mixed culture of non-Saccharomyces and Saccharomyces yeasts had good acceptance, those sequentially inoculated with malolactic bacteria displayed the greatest acceptability, with better fruity and floral aromas and high scores of equilibrium-harmony descriptor. Our study shown that sequential inoculation of O. oeni X2L after alcoholic fermentation by yeast mixed culture allowed better control on the sensory quality of wines produced from vineyards of Argentina Northwest.