Interactions between Saccharomyces and Oenococcus oeni strains from Amarone wine affect malolactic fer- mentation and wine composition

Introduction: The term malolactic fermentation (MLF) indicates a range of metabolic reactions by strains of lactic acid bacteria, usually Oenococcus oeni. MLF influences the organoleptic traits of wine and is necessary for the aging of red wines and certain white wines (LONVAUD-FUNEL 1999). However, the activities of malolactic bacteria (MB) in wine are affected by numerous factors, among which the effect of the yeast strain used to carry out the alcoholic fermentation (AF) has been investigated only sporadically (PATYNOWSKI et al. 2002). To preserve quality and typicalness of wines from specific areas appropriate indigenous yeasts and MB are used for controlling must fermentation and to promote MLF (AVEDOVECH et al. 1992; REGODÓN et al. 1997). In this context, we selected yeasts and MB for the production of Amarone wine in the Valpolicella area (Verona, Italy). This wine is produced according to the traditional technological practices, using partially dried grapes and fermenting must at low temperature. During spontaneous AF, a progressive growth pattern of Saccharomyces sensu stricto species has been observed (TORRIANI et al. 1999). MLF is a desirable feature, but it represents one of the most difficult steps to control in the making of Amarone wine. In the present study, the ability of Saccharomyces strains isolated from Amarone wine to induce MLF was evaluated in model fermentations. The effects of MLF on the metabolism of some secondary compounds of fermentation were also investigated.