Article ID: NSKKK-D-24-00054
We propose a method for calculating the temperature distribution in food containers by considering various heat transfer coefficients during heat sterilization. The CIHC method is a calculation method that incorporates the heat transfer coefficient, accounting for various heat transfer coefficient patterns on the container’s surface and container's thickness, to numerically calculate the temperature distribution inside the container during heat sterilization of food. In such sterilization processes, steam, pressurized air, and hot water are commonly used as heat transfer media at different flow rates for the sterilization of heat-sealed plastic cups and glass jars. Furthermore, the container material may exhibit high thermal insulation and be relatively thick. In the CIHC method, we represent the heat transfer coefficient as the thickness of the solid layer covering the container surface. To validate this method, we conducted an experiment using cylindrical plastic cups with three different thicknesses (0.5 mm, 1.0 mm, and 2.0 mm). We filled these cups with gelatinized starch and sterilized them at 120 ℃ for 30 minutes using a hot water immersion method. Using the temperatures in the sterilization chamber, we calculated the temperature distributions inside the gelatinized starch. The results suggested that the CIHC method is effective, as the calculated Fo values closely matched the measured values, and the root mean square errors for evaluating the time course of the temperature distribution were approximately 2 ℃.
