Physiological Changes of Saccharomyces cerevisiae by High Voltage Pulsed Electric Field Treatments

Abstract

High voltage pulsed electric fields (PEF) treatment is a promising non-thermal processing technology that can replace or partially substitute for thermal processes. The aim of this research was to investigate the microbial inactivation mechanisms by PEF treatment in terms of physiological changes to Saccharomyces cerevisiae. PEF was applied at the electric field strength of 50 kV/cm, treatment time of 56 µs and temperature of 40 o C. The microbial cells treated with PEF showed loss of salt tolerance on the cell membrane and collapse of the relative pH gradient on in-out of cells. Cell death or injury resulted from the breakdown of homeostasis, decreased H +-ATPase activity, and loss of glycolysis activity.