【摘要】 以橙汁为对象,采用自行研制的方波脉冲电源与连续式处理室进行PEF杀菌研究.通过对连续式处理室结构的优化,缓解处理过程中气泡引发的放电现象,减少处理过程中因放电引发的不良影响,为实验室设备连续工作提供必要的保证.试验结果表明,经过PEF处理(12.5 kV/cm,340μs)后的橙汁中的细菌菌落数由2200 cfu/mL下降到20 cfu/mL,酵母与霉菌的菌落数由1500cfu/mL下降到10 cfu/mL.处理后的橙汁在0℃低温贮藏20 d后,仍未发现微生物的明显增长,而且发现PEF处理的橙汁色泽、香气和口感均明显优于传统的瞬态热处理方法(90℃,15 s).更多还原

【Abstract】 A Pulsed Electric Fields(PEF) system self-designed with a square pulse generator and continuous chambers was described.The dielectric breakdown of gas bubbles entrapped in orange juice,as a limiting factor in PEF preservation,was investigated.A new electrode system was developed to reduce bubbles in chambers,which made it possible to work long time avoiding discharging and keeping process non-thermal.Pure naturally contaminated orange juice was pasteurized using PEF treatment at the electric field strength of 12.5 kV/cm for 340 μs pulsed treatment time.There are reductions in bacteria counts from 2 200 cfu/mL and 1 500 cfu/mL to 20 cfu/mL and 10 cfu/mL for yeast and mold counts individually.The treated juice,without aseptically filled,can be stored at 0 ℃ for 20 days without any significant microbial growth.Results of experiments show that the color,aroma and flavor of orange treated by PEF are significantly superior to that treated by conventional high temperature and short time method(performed at 90 ℃ for 15 s).更多还原