西瓜汁的脉冲磁场杀菌试验

Sterilization of Watermelon Juice by Pulsed Magnetic Fields

以西瓜汁脉冲磁场杀菌为例 ,研究了磁场强度、脉冲数和物料温度对杀菌效果的影响。结果表明 :(1 )随着磁场强度或脉冲数的增加 ,细菌残留数会出现一谷值 ,杀菌效果最好 ;之后随着磁场强度或脉冲数的进一步增加 ,杀菌效果反而变差 ;在细菌残留数出现峰值之后 ,杀菌效果再度变好。杀菌效果随磁场强度或脉冲数周期性的变化原因有待深入研究。 (2 )物料温度越高 ,微生物对磁场的敏感性越强 ,杀菌效果越好。 (3 )脉冲磁场对西瓜汁杀菌的主次因素为磁场强度 >脉冲数 >西瓜汁温度 ;最佳参数组合为磁场强度 7 5 9T ,脉冲数 1 5 ,西瓜汁温度 2 0℃ ,最佳参数下菌落总数和大肠菌群数可达到商业无菌要求。

Pulsed magnetic field was used for sterilization of watermelon juice. Influence of intensity, pulsed number of magnetic field and material temperature on sterilization effect was studied. The results indicated that:(1) At the lower end, as magnetic field intensity and pulsed number increase, the survival rate of bacillus will appear a minimum value, indicating optimal sterilization effect. Further increase of magnetic field intensity and pulsed number brought decreasing peptide solution during UF process, and molecular weight distribution of the peptides using SDS-PAGE electrophoresis, the selectivity and the separation effect were analyzed and evaluated. It was showed that the component with different molecular weight can be separated and purified by filtrating membrane, and UF can be used as a preliminary measuring method to analyze the molecular weight of the peptide solution.