Department of Food Science and Engineering, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.
PLoS One. 2018 Jun 25;13(6):e0198467. doi: 10.1371/journal.pone.0198467. eCollection 2018.
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 log10 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+, Mg2+) and Ca2+-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.
微芯片脉冲电场（MPEF）处理对毕赤酵母（Pichia rhodanensis，P. rhodanensis）致死和亚致死损伤的影响，在 100-500V 下处理 20-100 个脉冲，并研究了 MPEF 处理的潜在机制。在 500V 下处理 80 个脉冲，可使 P. rhodanensis 的减少量达到 6.48log10。碘化丙啶（PI）荧光染色证实，在 200V 下，亚致死损伤细胞的比率最高可达 27.2%。MPEF 可导致细胞形态和超微结构损伤，同时导致细胞酶、抗氧化酶活性和细胞膜流动性下降。细胞内化合物（蛋白质、核酸、K+、Mg2+）和 Ca2+-ATP 酶的泄漏随着电压的升高而逐渐增加，特别是上清液中蛋白质的比例从 2.0%增加到 26.4%。流式细胞术分析表明，MPEF 对膜电位有显著影响，但对非特异性酯酶没有明显影响。MPEF 可引起蛋白质二级结构的变化，同时使 DNA 的双螺旋结构变得松散和展开。这些结果为 MPEF 技术在非热加工技术在食品中的应用提供了理论指导。
