Transformation of chemical constituents of lychee wine by simultaneous alcoholic and malolactic fermentations.

This work examined for the first time the impact of malolactic fermentation (MLF) on the chemical constituents of lychee wine. Oenococcus oeni Viniflora Oenos (MLF inducer) and Saccharomyces cerevisiae MERIT.ferm were co-inoculated into lychee juice to induce simultaneous alcoholic fermentation (AF) and MLF. MLF did not affect sugar utilisation and ethanol production statistically (8.54% v/v for MLF and 9.27% v/v for AF). However, MLF resulted in dramatic degradation of malic and citric acids with concomitant increases of lactic acid, ethyl lactate and pH. The final concentrations of acetic and succinic acids between AF and MLF wines had no significant difference. The MLF wine contained significantly higher amounts of amino acids than the AF wine. More importantly, MLF significantly elevated the levels of potent aroma-active compounds including isoamyl acetate, linalool, geraniol and cis-rose oxide (to levels above or near respective detection thresholds), suggesting that MLF is an effective way of retaining the original lychee flavour.