Abstract: In this study, we investigated the effects of pomace maceration and mixed culture fermentation on the quality of pomegranate wine, made from Tunisian pomegranates. Single factor experiments and an orthogonal array design were jointly employed to optimize the process parameters for pomace maceration, which was conducted before fermentation. Mixed culture fermentation of pomegranate juice prepared under optimized conditions was conducted by co-inoculation of Torulaspora delbrueckii NX-1 or Metschnikowia pulcherrima NX-2 with Saccharomyces cerevisiae ES488 to explore the effects of different mixed starters on the aroma quality of pomegranate wine. The results showed that the optimum conditions for preparing pomegranate juice were maceration at 6 ℃ for 24 h after the addition of 200 g/L pomace. Mixed culture fermentation significantly increased the content of volatile compounds in pomegranate wine. In particular, co-fermentation with T. delbrueckii NX-1 and S. cerevisiae ES488 evidently increased the contents of the characteristic aroma components in pomegranate wine such as ethyl acetate, isoamyl acetate, ethyl caprylate and phenyl ethyl acetate, which imparted rich floral and fruity aromas to pomegranate wine, thereby improving the flavor complexity and richness. Meanwhile, pomace maceration followed by mixed culture fermentation could improve the antioxidant capacity of wine samples. In conclusion, the results of this study hold potential application value for improving aroma quality and antioxidant capacity of pomegranate wine.

Key words: pomegranate wine; pomace maceration; mixed culture fermentation; aroma quality