射频处理八角粉杀菌工艺

Research on Radio Frequency Heating to Inactivate Microorganisms in Aniseed Powder

利用作者所在实验室团队自主研发的射频设备探究了射频处理对八角粉的杀菌效果。结果表明,随射频(27.12 MHz)处理时间的增加,样品的温度不断增大,微生物致死率也显著增加。射频处理八角粉7 min,在最大限度保证样品质量的条件下可使样品中的微生物降低1.74 lg CFU/g。但是,RF处理样品加热的非均匀性一直是制约射频技术发展的关键问题。利用4个装有相同质量八角粉(37 g)的聚乙烯塑料袋(140 mm×100 mm)对称重叠在一起组成的模型来研究射频加热的均匀性。研究结果表明,样品内部和中心的温度明显高于表面温度,RF处理结合间歇的翻转可显著提高射频加热的均匀性。射频技术是一种很有前景的低水分活度食品新型杀菌技术。

The effect of radio-frequency(RF)heating to inactive microorganisms was investigated.The results showed that the temperature of the sample increased with the extension of RF(27.12 MHz)treatment time,and the number of survival microorganisms reduced significantly.The level of microbial inactivation was greatly reduced by 1.74 lg CFU/g with insignificant color degradation after RF heating for 7 min.However,non-uniform heating of RF treatment is still a major problem for restricting development of the RF technology.Four of the same polyethylene plastic pouches(140 mm×100 mm)packaged with the same weight of sample(37 g)were added together,which was used as a model of low water activity(Aw)food for studying the RF heating uniformity.The non-uniform heating pattern was validated,characterized by much higher temperatures in the interior and center of the food powder package than that in the exterior surface.Rolling over during RF treatment proved to be effective for improving the heating uniformity.Therefore,RF heating is a new promising technology,which is suitable for sterilization of the low Aw food.