Abstract:The effects of the freeze concentration technology on the quality of Litchi wine were studied. Three different winemaking processes, direct fermentation, fermentation-freeze concentration, and freeze concentration-fermentation led to the production of fermented Litchi wine, fermented-concentrated Litchi wine and concentrated-fermented Litchi wine, respectively, from Litchi juice. Then comparative analyses of physicochemical indicators, amino acids content and volatile substances and sensory evaluation of 3 Litchi wines were conducted. The obtained results showed that the fermented Litchi wine had an alcohol content of 8.48 %, total acid of 4.80 g/L, tannin content of 0.53 g/L, total free amino acid of 40.38 mg/L and the alcohol-ester ratio of 0.86, with a light fruity smell and an ordinary mouthfeel. While the fermented-concentrated Litchi wine and the concentrated-fermented Litchi wine had 16.10% and 16.47% alcohol, 9.57 g/L and 7.70 g/L total acid, 1.02 g/L and 1.13 g/L tannin content, 102.97 mg/L and 493.17 mg/L total free amino acid, respectively, which were significantly higher than those of the fermented Litchi wine (p<0.05). The fermented-concentrated Litchi wine had an alcohol-ester ratio of 0.50 with an increase of wine aroma, but the acidity and content of undesirable flavor were high (which didn’t taste good). The concentrated-fermented Litchi wine had the alcohol-ester ratio of 0.26 with a strong fruity smell and full-bodied mouthfeel (superior to the other two Litchi wines). The study indicates the freeze concentration before fermentation could result in the production of Litchi wine of high quality.
