Proceedings Volume 2010 (format .pdf) - SimpBTH

wine acids. Usually in the process of must fermenting there are more yeasts thatparticipate. In the case when the grapes must ferments with just a selected yeaststrain, the wine is not sufficiently smooth.Lately the reseach regarding the grapes micro-flora has been increased, sothat we can now isolate yeasts with superior qualities which are needed for thealcoholic fermentation of the grapes must.It was observed that the yeasts which arepresent natively on the grapes do not always lead to an efficient fermentation,especially the ones from the rainy or cold autumns.MATERIALS AND METHODSThe research in this study were using three Saccharomyces bayanus (SB1,SB2, SB3) yeast strains which were isolated from the grapes types Iordana, WhiteFeteasca and Royal Feteasca from the Sebes-Apold vineyard. The growingenvironments we used were for the refference strain (M1) - must malt, M2 – mustmalt in which we added thiamine in quantity of 0,05 mg per liter, M3 – must maltin which we added magnesium sulphate (MgSO 4 x7H 2 O) 0,5 g per liter.The biological strains which we considered were monitored during 10 daysin the Sartorius fermenter (equipped with sensors for: temperature, biomass, CO 2 ,oxygen) at the temperature of 22°C.RESULTS AND DISCUSSIONSThe results emphasized a series of modifications in the development curveof the three types of yeasts, depending on the chemical composition of the growingenvironment. The M1 environment (refference one) presents a minimum amount ofbiomass comparing with the M2 and M3 environments. The below graphics showthis variation during the entire development and multiplication cycle of the yeastcells. The M2 environment in which we added thiamine, is the optimum one,especially during the time interval 5 th to 7 th fermentation days.A definitive rolsplays also the addition of the MgSO 4 x7H 2 O in the growing environments, theaccumulation of biomass being faster than in the case of the refferenceenvironment, providing stability to the technological process and also providing thepossibility to obtain higher quality wines, or for improvement of the secondaryfermentation process.154