Characterization of wines produced by mixed culture of autochthonous yeasts and Oenococcus oeni from the northwest region of Argentina.

Two autochthonous yeasts from the northwest region of Argentina, Kloeckera apiculata mc1 and Saccharomyces cerevisiae mc2, were used as pure or mixed starter cultures in microvinification trials conducted in Malbec red must. Also, the effect of Oenococcus oeni X(2)L was evaluated. S. cerevisiae mc2 showed adequate growth and fermentative activity in single and composite fermentations, producing standard concentration of ethanol. The amount of esters was higher in fermentations conducted using mixed yeast starters. Independent of the timing of inoculation of O. oeni, this malolactic bacterium completely depleted malic acid. Sensory evaluation indicated that young wines fermented with mixed yeast cultures and sequential inoculation of O. oeni were preferred, achieving the highest scores for positive descriptors and they allowed better control of the sensory quality. Consequently, this study proposes inclusion of autochthonous K. apiculata mc1 as an adjunct culture to S. cerevisiae mc2 during Malbec must fermentation to improve the organoleptic properties of red wines. Furthermore, sequential inoculation of O. oeni X(2)L should be carried out after completion of the alcoholic fermentation to enhance sensory characteristics.