摘要
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及营养成分的影响。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 15 ,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。 (4 )脉冲磁场对西瓜汁中还原性Vc和色素有一定的影响 ,但影响不大 ;对西瓜汁中可溶性固性物含量和 pH值几乎没有影响。
Taking the pulsed magnetic field sterilization of watermelon juice as an example , Influence of intensity and pulsed number of magnetic field and material temper ature on sterilization effect and juice’s nutrient component was studied. The r esults point out that: (1) As magnetic field intensity and pulsed number, the su rvival rate of bacillus will appear a minimum value, that is sterilization effec t best. Then on the contrary sterilization effect becomes bad while magnetic fie ld intensity and pulsed number increase further. After a peak value of survival rate of bacillus, sterilization effect becomes good again. The reason about seas onal change of sterilization effect as intensity and pulsed number of magnetic f ield needs further study. (2) The higher material temperature, the more distinct sensitivity of microorganism on magnetic field, and the better sterilization ef fect. When temperature raises from 35℃ to 40℃, the killing ability of pulsed m agnetic field on microorganism increases rapidly. (3) Factor order of sterilizat ion effect of the pulsed magnetic field on watermelon juice is: magnetic field i ntensity> pulsed number> material temperature. Optimal parameter assemble is mag netic field intensity 7.59T, pulsed number 15 and material temperature 20℃. Und er Optimal parameter assemble, aerobic bacterial count and coliform bacteria hav e satisfied requirements of food business. (4) Influence of pulsed magnetic fiel d on the deoxidized vitamin C and color exists, but smaller. Influence on solubl e solids content and pH value is no almost.
出处
《微波学报》
CSCD
北大核心
2004年第3期82-85,共4页
Journal of Microwaves
基金
江苏省教育厅"青蓝工程"学术带头人基金项目
