Ice structuring proteins from plants: Mechanism of action and food application

Application of ice structuring proteins (ISPs) as a food preservative has shown potential to enhance the quality of frozen food and desserts during freezing storage, transport, and thawing. One of the main advantages of ISPs for the food industry is that they are fairly active in very low amounts, which could make these new food ingredients very cost-effective. Therefore, ISPs have gained much attention in food science and their use has become more and more feasible. ISPs have been discovered in many cold tolerating biological systems such as fish, insects and plants, which all exhibit ice recrystallization inhibition, and also in some cases, thermal hysteresis and ice nucleating activities. This review discusses cold stress and cold tolerance in plants, different mechanisms of actions of ISPs and homologies to other structurally identified proteins, which lead to the dual role of ISPs in plants as ice recrystallization inhibitors and pathogenesis-related proteins or enzymes. Ice crystallization and recrystallization (growth of larger ice crystals at the cost of “restructuring” of other ones), interaction of ice crystal and ISPs, ice recrystallization inhibition and thermal hysteresis assays, and application of ISPs in different food products are also discussed. To-date there is no data available to report toxicity or to challenge the safety of these “novel” food ingredients.

► Ice structuring proteins (ISPs) can be found in many cold tolerant plants.
► The anchored clathrate mechanism may explain ISP-ice binding.
► DSC can be used to assay both thermal hysteresis and ice structuring activities.
► ISPs offer food manufacturers a novel ingredient for ice recrystallization control.
► There is no research to suggest that ISPs are toxic or allergenic for humans.