Temperature management is an important tool in governing the processes of food preservation as it can directly affect the microbiological, biochemical and physiological reaction pathways which are responsible for the deterioration in food quality, and preserving the nutritional value, appearance, texture and flavour of the food product. Unlike the common food industrial heat treatments such as pasteurisation and blanching, it is important to note that the freezing does not result in complete death of the microorganisms existing in food. It is instead an effective process in reducing the microbial and biochemical activities that present in food. Specifically, the temperature drop in food along with the decreased water availability due to ice formation could effectively reduce any microbial activity and enzymatic reactions in food.

 

Numerous theories have been established from the study of freezing. The approaches taken in the various studies were indeed based on different assumptions, and only a few topics are of considerable interest for the perspective of a food engineer.

 

• The determination of the initial freezing point of a particular food product could be expected to be different from the freezing point of pure water due to the presence of solutes in the food matrix that reduce the freezing point. As different food matrices result in different initial freezing points, the duration required for food to reach a solidified frozen state under a given freezing condition varies accordingly.

 

• The determination of the freezing time required for a particular food system. The degree of familiarity with the temperature change profile that a particular food product undergoes during freezing allows for the fundamental study of the process of freezing. Each food units given will not necessarily undergo uniform freezing.

 

• The determination of the energy required to achieve the degree of freezing in a particular food product (for selecting appropriate refrigeration equipment).