Free and Immobilized Cells of Torulaspora delbrueckii and Lachancea thermotolerans in Sparkling Wine: Innovative Application in Secondary Bottle Fermentation.

Sparkling wine production involves secondary alcoholic fermentation, during which carbon dioxide is trapped, creating effervescence and enhancing sensory complexity. This study evaluated the impact of Torulaspora delbrueckii and Lachancea thermotolerans yeast species using free and immobilized cells in secondary fermentation of sparkling wine, in comparison with Saccharomyces cerevisiae. Immobilized S. cerevisiae enabled faster refermentation compared to free cells, while immobilization resulted in a slower process in non-Saccharomyces strains. Biomass monitoring showed stable viable cells for immobilized S. cerevisiae during fermentation, while non-Saccharomyces strains showed a consistent reduction. Volatile profiles were positively influenced by immobilization using S. cerevisiae strains, which produced a constant increase in key aroma compounds, such as geraniol and ethyl acetate, throughout fermentation. Non-Saccharomyces strains contributed to enhanced fruity and floral aromas with variations in volatiles during refermentation. Sparkling wines fermented with immobilized L. thermotolerans were noted for ripe fruit aromas, while T. delbrueckii increased floral notes. S. cerevisiae fermentations showed higher acidity and balanced structure. These findings highlight the influence of yeast species and the yeast immobilization procedures in secondary fermentation, modulating fermentation dynamics and aroma development, and offer a promising strategy to tailor sparkling wine quality and sensory complexity.