Effects of Torulaspora delbrueckii co-fermented with Saccharomyces cerevisiae on physicochemical and aromatic profiles of blueberry fermented beverage

To investigate the effects of mixed fermentation with T. delbrueckii on aroma profiles of blueberry fermented beverage, five fermentations were conducted: monoculture of T. delbrueckii and S. cerevisiae, respectively; co -inoculation of two strains; sequential inoculation of two strains at time intervals of 24 h and 48 h, respec-tively. Compared with pure S. cerevisiae fermentation, ethanol level was decreased by up to 1.1% vol., while total anthocyanins were increased by 27.7%-85.0% in mixed fermentations. Marker aroma compounds in different fermentations with relative odor activity values higher than 1were identified. T. delbrueckii significantly decreased volatile acid content (especially acetic acid) by 22.2%-83.3%. Ethyl 3-methylbutanoate, ethyl hex-anoate and ethyl octanoate, in pure T. delbrueckii fermentation were significantly decreased, while their con-centrations were increased by 1.6-4.4 folds in sequential fermentations. Besides, linalool, rose oxide, benzeneacetaldehyde were significantly increased by sequential fermentation, which was associated with the enhancement of fruity and sweet notes.

Automated summary

This study investigated the effects of mixed fermentation with T. delbrueckii on aroma profiles of blueberry fermented beverage. Five fermentations were conducted to compare different fermentation methods. The results showed that mixed fermentation resulted in a decrease in ethanol level and an increase in total anthocyanins. Marker aroma compounds were identified, and volatile acid content was significantly decreased by T. delbrueckii. Sequential fermentation also led to an increase in certain aroma compounds associated with fruity and sweet notes.