A Modified Fictitious Heat Flow Method for Numerical Calculation of Food Freezing Processes

摘要

Freezing processes play an important role in processing aqueous foods. However, their mathematical description is difficult because of the heterogeneous, biological nature of foods. A freezing point lower than that of pure water and a broad freezing range are typical phenomena. The author proposes a new modeling approach for freezing foods based on the fictitious heat flow model, taking into consideration the broader freezing range. The ideas of the model and calculation procedure are briefly described. Suitability of the model approach is checked using data of freezing processes of cylinders made from meat and sausages. Temperature courses calculated by the model fit well with temperatures measured at different locations within the product. Calculated model parameters characterizing the freezing behavior are uniform within the product groups, but differ distinctly between meat and sausages. The differences can be explained by product properties.The model enables the simulation of freezing processes with respect to local temperature distribution and ice content in a wide range of freezing conditions.