ABSTRACT
Food preservation by freezing dates back to prehistoric times when primitive man observed that at continued low temperature climates, perishable foods would keep in good condition as long as they were maintained in the frozen state. Freezing processes can be divided into three distinct phases: a precooling period; a phase change period; and a tempering period. Any model for the prediction of freezing time requires reliable values of thermophysical properties of food material. Freezing time represents the residence time that a food product is exposed to the freezing environment to achieve the desired level of freezing. The freezing and thawing of food product is complex because of continuous changes in thermophysical properties during the process. In food freezing processes the product temperature is lowered from its original value to the storage temperature. The carton freezers are in-line continuous freezing systems used for the handling of products packaged in cartons.
