Control of Ice Nucleation for Subzero Food Preservation

Freezing processes have long been employed for the preservation of foods, providing minimum nutrition loss with a long shelf life period. Freezing plays an essential role in ensuring the safety of food products in all regions of the world. Nonetheless, slow freezing rates and frequently freezing/thawing lead to permanent physicochemical changes, damage of structure, degradation of nutrition values, and color changes through the formation of large ice crystals in food matrix during the cold storage. The size of ice crystals is highly related to the duration of phase transition and degree of supercooling. This paper reviews that the degree of supercooling and nucleation temperature can be controlled by positive or negative pressure and vibration of the dipole and dipole rotation water molecule techniques. Controlling nucleation temperature and suppression of ice crystals in the food matrix could not be achieved by current freezing methods such as air blast, contact, and immersion freezing in the food industry. These present freezing methods are especially focused on increasing the heat transfer rate in foods. Rapid freezing technology may depend on the size and shape of food. However, the size of ice crystals and the suppression of nucleation could be achieved by alternative freezing technologies to overcome the drawbacks of current freezing technologies in the food industry. Conventional freezing technologies can be replaced by emerging freezing techniques, ultrasound irradiation, high pressure, electric field, magnetic field, and microwave-assisted freezing to control the properties of the nucleation and degree of supercooling in the food industry.