Optimization of fermentation-relevant factors: a strategy to reduce ethanol in red wine by sequential culture of Hanseniaspora uvarum/S.cerevisae native yeast.

MESTRE M.V.; MATURANO Y.P.; KUCHEN, B.; MERCADO L. A.; TORO M.E.; COMBINA M.; VAZQUEZ F.

Bariloche

Simposio; 34th International Specialized Simposium on Yeast (34 ISSY).; 2018

CONICET

Current consumer preferences are determined by well-structured, full-bodied wines with a rich flavor and with reduced alcohol levels. One of the strategies to obtain wines with reduced ethanol content is sequential inoculation of non-Saccharomyces and Saccharomyces cerevisiae yeasts. However, different factors could affect the production of metabolites like ethanol, glycerol and acetic acid by inoculated yeasts. In order to obtain low alcohol wines without quality loss, the aims of our study were: i) to optimize the fermentative factors to improve the performance of non-Saccharomyces yeasts prior S. cerevisiae inoculation to reduce final ethanol in wines; ii) to validate the optimized factors in grape must; and iii) to assess sensory quality of the wines obtained. Hanseniaspora uvarum BHu9 and S. cerevisiae BSc114 previously selected were used. A Box-Behnken experimental design was employed to assess the effects of three independent factors (fermentation temperature, time of permanence and initial inoculum size of the BHu9 population at the beginning of the process, prior to inoculation with BSc114). The optimal conditions to obtain lowest ethanol levels were: temperature of 25°C, initial inoculum size of 5x10 6cells/mL and a time of permanence of 48h 37min of Bhu9. Then BSc114 yeast strain was inoculated at a concentration of 2x106 cells/mL to finish the process. After optimization, the three factors assayed were validated at lab-scale in grape must cv Malbec. Single culture fermentations of BSc114 was used as control. Wines obtained using sequential culture registered ethanol levels significantly lower than control treatment (p