Electroporation Assisted Improvement of Freezing Tolerance in Yeast Cells

Prolonged storage of frozen dough worsens the structure of thawed dough. The main reason is the inhibition of yeast activity. In this study we investigated applicability of pulsed electric field treatment for introduction of cryoprotectant into yeast cells. We showed that pre-treatment of cells suspended in a trehalose solution improves freezing tolerance and results in higher viability after thawing. Viability increased with rise in electric field strength (from 3 to 4.5 kV/cm) and incubation time (from 0 to 60 min) after exposure. Pretreatment resulted in lower decrease in the viability of thawed cells, viability of untreated cells dropped to 10%, while pre-treatment with PEF and trehalose tripled the viability.