Ou Qi-Xing, Nikolic-Jaric Marija, Gänzle Michael
University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada.
HIECO Ltd., Calgary, Alberta, Canada.
Bioelectrochemistry. 2017 Jun;115:47-55. doi: 10.1016/j.bioelechem.2016.12.005. Epub 2016 Dec 30.
This study aimed to determine how electric field strength, pulse width and shape, and specific energy input relate to the effect of pulsed electric fields (PEF) on viability and membrane permeabilization in Candida humilis and Saccharomyces cerevisiae suspended in potassium phosphate buffer.
Cells were treated with a micro-scale system with parallel plate electrodes. Propidium iodide was added before or after treatments to differentiate between reversible and irreversible membrane permeabilization. Treatments of C. humilis with 71kV/cm and 48kJ/kg reduced cell counts by 3.9±0.6 log (cfu/mL). Pulse shape or width had only a small influence on the treatment lethality. Variation of electric field strength (17-71kV/cm), pulse width (0.086-4μs), and specific energy input (8-46kJ/kg) demonstrated that specific energy input correlated to the membrane permeabilization (r=0.84), while other parameters were uncorrelated. A minimum energy input of 3 and 12kJ/kg was required to achieve reversible membrane permeabilization and a reduction of cell counts, respectively, of C. humilis.
Energy input was the parameter that best described the inactivation efficiency of PEF.
This study is an important step to identify key process parameters and to facilitate process design for improved cost-effectiveness of commercial PEF treatment.
本研究旨在确定电场强度、脉冲宽度和形状以及比能量输入与脉冲电场（PEF）对悬浮于磷酸钾缓冲液中的矮小假丝酵母和酿酒酵母的活力及膜通透性的影响之间的关系。
使用带有平行板电极的微型系统处理细胞。在处理前后添加碘化丙啶以区分可逆和不可逆的膜通透性。用71kV/cm和48kJ/kg处理矮小假丝酵母可使细胞计数减少3.9±0.6对数（cfu/mL）。脉冲形状或宽度对处理致死率的影响很小。电场强度（17 - 71kV/cm）、脉冲宽度（0.086 - 4μs）和比能量输入（8 - 46kJ/kg）的变化表明，比能量输入与膜通透性相关（r = 0.84），而其他参数不相关。分别需要3kJ/kg和12kJ/kg的最小能量输入才能实现矮小假丝酵母的可逆膜通透性和细胞计数减少。
能量输入是最能描述PEF灭活效率的参数。
本研究是确定关键工艺参数以及促进工艺设计以提高商业PEF处理成本效益的重要一步。
