초록
The batch fermentation process, inoculated by Pulsed Electric Field (PEF) treated wine yeasts (Saccharomyces cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions ([Y]=0.012g/L) at the electric field strengths of E=100 and 6000V/cm using the same treatment protocol (number of pulses n=1000, pulse duration t<SUB>i</SUB>=100μs, and pulse repetition time Δt=100ms). Electrical conductivity was increasing during and after the PEF treatment, which reflected cell electroporation. Then, fermentation was run for 150h in an incubator (30<SUP>o</SUP>C) with synchronic agitation. Electro-stimulation was revealing itself by the improvement of fermentation characteristics, and thus increased yeast metabolism. At the end of the lag phase (t=40h), fructose consumption in samples with electrically activated inoculum exceeded that of the control samples by ~2.33 times for E=100V/cm and by ~3.98 for E=6000V/cm. At the end of the log phase (120h of fermentation), ~30% mass reduction was reached in samples with PEF-treated inocula (E=6000V/cm), whereas the same mass reduction of the control sample required approximately 20 extra hours of fermentation.