Paola DOMIZIO1, Lorenzo Portaro1, Francesco MAIOLI1, Valentina CANUTI1, Monica PICCHI1, Livio Lencioni1, Ilaria Mannazzu2
1 Department of Agricultural, Food, Environmental, and Forestry Sciences and Technologies – University of Florence, via Donizetti, 6 – 50144 Firenze (Italy)
2 Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari (Italy)
Email contact: paola.domizio[@]unifi.it
AIM: In the present work Schizosaccharomyces japonicus and Saccharomyces cerevisiae were inoculated simultaneously or in sequence in mixed fermentation trials with the aim of testing their ability to improve the overall quality of red wine, in particular of Sangiovese wine.
METHODS: The impact of simultaneous and sequential inoculations on growth and fermentation kinetics and on the analytical and sensory profiles of the experimental wines was evaluated at the end of the alcoholic fermentation and 24 months after bottling with standard methods.
RESULTS: S. japonicus affected S. cerevisiae growth and fermentative capability only in the sequential fermentation. The experimental wines produced with S. japonicus and S.cerevisiae in simultaneous and sequential mixed fermentation reached concentrations of total polysaccharides respectively two- and three-fold greater than those obtained with pure cultures of S.cerevisiae. Moreover, the non-Saccharomyces yeast modulated the concentration of some of the most important wine volatile compounds. At the end of the alcoholic fermentation, ethyl acetate was significantly higher in the mixed fermentation wines in respect to the level acceptable for a young red wine. However, this metabolite underwent considerable hydrolysis during the two-years aging in bottle, with a marked decrease in its concentration. In agreement, mixed fermentation wines as compared to the control wines showed no significant differences for the ethyl acetate perception evaluated by sensory analysis carried out 24 months after bottling. Hydrolysis–esterification equilibrium in mixed fermentation wines caused an increase of acetate esters compounds responsible for fruity aroma. These ester compounds reached significantly higher concentrations in both mixed fermentation wines than in the control wine inoculated with S. cerevisiae. Moreover, all mixed fermentation wines were perceived as having lower mouthfeel sensation of astringency compared to those obtained with S. cerevisiae, possibly due to the higher polysaccharides content.
CONCLUSIONS: Based on the evidence that after 2 years of aging, mixed fermentation wines presented an increase in color stability and the concentration of fruity aroma and a decrease in astringency, the combined utilization of Sch. japonicus and S. cerevisiae might represent an innovation for the improvement of the aging stability of Sangiovese wine.