  The batch fermentation process, inoculated by pulsed electric field (PEF)
treated wine yeasts (S. cerevisiae Actiflore F33), was studied. PEF treatment
was applied to the aqueous yeast suspensions (0.12 % wt.) at the electric field
strengths of E=100 and 6000 V/cm using the same pulse protocol (number of
pulses of n=1000, pulse duration of ti=100 mks, and pulse repetition time of
dt=100 ms). Electro-stimulation was confirmed by the observed growth of
electrical conductivity of suspensions. The fermentation was running at
30{\deg}C for 150 hours in an incubator with synchronic agitation. The obtained
results clearly evidence the positive impact of PEF treatment on the batch
fermentation process. Electro-stimulation resulted in improvement of such
process characteristics as mass losses, consumption of soluble matter content
({\deg}Brix) and synthesis of proteins. It also resulted in a noticeable
acceleration of consumption of sugars at the initial stage of fermentation in
the lag phase. At the end of the lag phase (t=40 hours), consumption of
fructose in samples with electrically activated inocula exceeded fructose
consumption in samples with control inocula by 2.33 times when it was activated
at E=100 V/cm and by 3.98 times after treatment at E=6000 V/cm. At the end of
the log phase (120 hours of fermentation), 30% mass reduction was reached in
samples with PEF-treated inocula (E=6000 V/cm), whereas the same mass reduction
of the control sample required approximately, 20 hours of extra fermentation.
The possible mechanisms of electro-stimulation are also discussed in details.
