Measuring and controlling ice crystallization in frozen foods: A review of recent developments

Fresh food are perishable, and freezing is a popular way of maintaining the quality and safety of foods. However, ice crystals formed during freezing may result in the breakage of cell structure, leading to quality deterioration. In order to better understand the relationship between microstructure and ice crystals and obtain high quality food products, it is critical to effectively measure and control the behavior of ice crystals. In the current review, the principles of measuring methods including optical and electron microscopy, electromagnetic spectroscopy, differential scanning calorimetry (DSC) and online techniques are introduced, novel technologies based on ultrasound, high pressure, and electromagnetic fields, as well as biological proteins to control the formation of ice crystals by inducing or suppressing ice crystallization are presented. Future prospects on measuring and controlling ice crystallization are also discussed. By obtaining the moisture behavior information with NMR, Raman and DSC and direct images or network structure of ice crystal, these direct and indirect measurements can characterize ice crystals in multi-perspectives, providing constructive information on the mechanisms of the freezing process. In addition, advanced novel freezing technologies show great promise in improving the crystallization process during freezing of foods. It is thus hoped that this review could provide better understanding on ice crystallization in frozen products, leading to the optimization of the freezing process for the frozen food industry.