A new approach for the numerical calculation of freezing and thawing processes of foods using a modified fictitious heat flow method

Abstract

Freezing and thawing processes play an important role in processing of 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 calculation approach for freezing and thawing of foods based on the fictitious heat flow model and taking into consideration the broader freezing range. The ideas of the model are presented and explained. The suitability of the model is checked using freezing/thawing processes of a whole egg product in a bucket. A good fit of temperature courses measured within the bucket could be observed. A freezing curve obtained implicitly from the model calculations shows a similar course to those measured by DSC. The model enables the simulation of both freezing and thawing processes with respect to local temperature distribution and ice content under a wide range of conditions with respect to geometry, heat transfer, temperature range and others.