Improving overproduction of glycerol by combining Torulaspora delbrueckii with Saccharomyces in dried grape dessert wine

Combined yeast strains were to improve overproduction of glycerol in dessert wine fermentation from dried grape of Vitis vinifera 'Tempranillo'. The initial sugar concentration was approximately 330-350 g L^‑1. The non-Saccharomyces Torulaspora delbrueckii 291 and sequential culture with three different industrial Saccharomyces cerevisiae (ICV-GRE, V1116, M69) were added, and incubated at 20°C. The modeling of glycerol and acetic acid profiles from dried grape dessert wine by high performance liquid chromatography were analyzed. The use of combined yeast strains fermenting in high-sugar concentration significantly influences the glycerol and acetic acid production in wine. It impacted the reduction of glycerol content compared to the pure Saccharomyces, while ethanol was low with the remaining of high reducing sugar. This may encourage osmotic pressure circumstance, resulting in a slight increase in acetic acid. This study demonstrates that the fermentation of T. delbrueckii 291 and S. cerevisiae together could be applied in dried grape dessert wine production to improve fermentation behavior, as well as the accumulation of glycerol and acetic acid.