Studies on the pure fermentation and aroma contributions of Torulaspora delbrueckii killer yeasts with high enzymatic activity in different white wine varieties

Yeast enzyme activity is pivotal in shaping wine aromas. To elucidate the contribution of T. delbrueckii to aromas during pure fermentation, this study comprehensively evaluated the fermentation performance and enzymatic characteristics of its indigenous and commercial strains. Representative strains were screened to analyze their impact on volatile aroma compounds and overall wine quality. Except for residual sugar and alcohol, no significant differences were observed in the basic physicochemical indicators among the groups. The β -glucosidase and esterase activities of the optimized indigenous strain were 0.76 and 0.63 times higher than the commercial control strain, respectively. The resulting wine exhibited significantly higher concentrations of total volatile aroma compounds, with key constituents such as phenylethanol and ethyl octanoate present at 0.3–0.8 times higher than the control. Sensory evaluation further confirmed that floral and fruity aromas were more prominent in this group of wine samples, indicating the strain's potential to enhance wine aroma complexity. • T. delbrueckii were screened based on oenological and enzymatic properties. • TD6 showed superior extracellular enzyme activity and aroma enhancement potential. • Pure fermentation of T. delbrueckii increased the content of key aroma compounds. • The richest in esters and alcohols of all pure fermented wines. • T. delbrueckii is of value in white wine aroma complexity and quality enhancement.