轴向旋转对液态罐头食品热杀菌过程的影响

Effect of Axial Rotation on Thermal Sterilization of Canned Liquid Food

以水、0.85%CMC和2.5%CMC溶液为研究对象,基于COMSOL Multiphysics软件建立三维传热模型模拟液态罐头食品的热杀菌过程。采用无线温度传感器对热杀菌过程中罐内中心温度的变化进行验证,发现模型很好地拟合了罐内中心点温度的变化。在此基础上,模拟罐头在旋转速度为1,2.5,5 r/min的条件下对热杀菌过程的影响。结果表明,相对静止杀菌而言,轴向旋转可有效提高液态罐头食品的传热速率,并且提升效果与液体食品的黏度有关。对于纯水而言,旋转提高效果较小;对于黏度较大的食品,速度很小的旋转即可大幅度缩短杀菌时间。

A three-dimensional heat transfer model was established to simulate thermal sterilization of model food （water, 0.85% sodium carboxy-methyl cellulose （CMC） and 2.5% CMC solution） in this paper. Experiments were run with water, 0.85% CMC and 2.5%CMC solution in cans and the temperature of center point were determined by the wireless temperature recorder. The results show that temperature profiles obtained by COMSOL Multiphysics were in good agreement with experimentally determined values. After validation, rotation of water, 0.85% CMC and 2.5% CMC solution in cans during thermal sterilization were simulated at 1, 2.5 and 5 rpm respectively. These results revealed that heat transfer rate was improved with axial rotation to some extent and the promotion effect was related to the viscosity of the liquid food. The promotion effect was little for water, however sterilization time was shorten by a large extent even with a low speed in axial rotation for 0.85% and 2.5% CMC solution.