Electro-stimulation of Saccharomyces cerevisiae wine yeasts by Pulsed Electric Field and its effect on fermentation performance
| Autor: | Mattar, J., Turk, M., Nonus, M., Lebovka, N. I., Zakhem, H. El, Vorobiev, E. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | 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. Comment: 12 pages, 5 figures. This article has been withdrawn at the request of the editor of the journal and authors |
| Databáze: | arXiv |
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