Improvement of wine organoleptic characteristics by non-Saccharomyces yeasts

In traditional winemaking, natural fermentation of grape juice is carried out by a sequence of different yeast species. The early stages are dominated by non-Saccharomyces yeasts and are replaced by Saccharomyces cerevisiae that finish the fermentation process. In this chapter was evaluated the kinetics and metabolic behavior of Kloeckera apiculata mc1 and S. cerevisiae mc2 in composite culture. In this condition, K. apiculata showed a higher viability through the fermentation; however the cell density of both yeasts decreased. This behavior was not due to ethanol concentration, killer toxins production or competition for assimilable nitrogenous compounds between both yeasts. Despite the consistent production of secondary products by single culture of K. apiculata, desirable concentrations of these compounds were observed in mixed culture. The influence of temperature and SO2, on growth and metabolism of both wine yeasts was dependent of the culture type. Malolactic fermentation conducted by Oenococcus oeni is important enhancing wine quality, microbiological stability and flavour. The inclusion of K. apiculata mc1 as adjunct culture of S. cerevisiae mc2 during must fermentation improved the organoleptic characteristics of wines produced from vineyards in Argentina Northwest. In addition, sequential inoculation of O. oeni X2L allowed better control on the sensory quality of the fermented product.