Open AccessInactivation of Pichia rhodanensis in relation to membrane and intracellular compounds due to microchip pulsed electric field (MPEF) treatment
Author(s) -
Ning Zhu,
Ning Yu,
Yue Zhu,
Yulong Wei,
Haiping Zhang,
Aili Sun
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0198467
Subject(s) - propidium iodide , intracellular , flow cytometry , biophysics , cell membrane , chemistry , apoptosis , biochemistry , membrane , biology , microbiology and biotechnology , programmed cell death
The effect of microchip pulsed electric field (MPEF) treatment on lethal and sublethal injury of Pichia rhodanensis (P . rhodanensis) were employed under 100–500 V for 20–100 pulses and the underlying mechanism of MPEF treatment was investigated as well. A 6.48 log 10 reduction of P . rhodanensis was achieved at 500V for 80 pulse. The fluorescent staining with Propidium Iodide (PI) verified that the rate of sublethal injury cells maximum up to 27.2% under 200 V. MPEF can cause the damage of cell morphology and ultrastructure, meanwhile causing a decrease in cellular enzymes, antioxidant enzyme activity and cell membrane fluidity. The leakage of intracellular compounds (protein, nucleic acid, K + , Mg 2+ ) and Ca 2+ -ATPase gradually increased as the growth of voltage, especially the proportion of protein in the supernatants increased from 2.0% to 26.4%. Flow cytometry analysis showed that MPEF has significant effect on membrane potential, but no obvious influence on non-specific esterase. MPEF can cause the changing of the secondary structure of protein, at the same time, double helix structure of DNA became loose and unwinding. These results provide a theoretical guidance for the widespread using of MPEF technology in the application of a non-thermal processing technique for food.