Impact of simultaneous and sequential fermentation with Torulaspora delbrueckii and Saccharomyces cerevisiae on non-volatiles and volatiles of lychee wines

- Saccharomyces cerevisiae mono- and simultaneous cultures showed highest fermentative capacity.
- Torulaspora delbrueckii monoculture had the highest capacity to retain terpenoids.
- Sequential culture reached a balance to keep terpenoids and to form alcohols and esters.

This study evaluated the effects of simultaneous and sequential fermentation with Torulaspora delbrueckii PRELUDE and Saccharomyces cerevisiae MERIT.ferm non-volatile and volatile components of on lychee wines. T. delbrueckii monoculture showed lower fermentative activity than S. cerevisiae alone with regard to growth, nitrogen utilization, production of alcohols, volatile acids and esters. However, T. delbrueckii monoculture had a better ability to retain the odour-active terpenes and terpenoids derived from lychee fruits. The lychee wine fermented with simultaneous culture had a similar characteristic to that of the S. cerevisiae monoculture. In sequential fermentation, prior inoculation of T. delbrueckii played an important role in lowering volatile acids (odour activity value, OAV<1) and retaining terpenoids (OAV, 1.2-5.8). Subsequent inoculation of S. cerevisiae significantly increased the production of ethanol (>8 mL/100 mL), higher alcohols (isoamyl alcohol and 2-phenylethyl alcohol) and esters (ethyl esters of octanoate, decanoate and hexanoate, and 2-phenylethyl acetate), relative to the T. delbrueckii monoculture. Therefore, sequential fermentation could accord the wine volatiles from both lychee fruits and biotransformation.