Content of research

Silver iodide and ice-nucleating bacteria promote heterogeneous nucleation of water, which in turn promotes freezing of water. Although several compounds that have inhibitory effects on such ice-nucleating activity have been reported, the polyphenol used in this study is a relatively small molecule that can reduce the freezing temperature of aqueous solutions by several degrees by suppressing the activity of coexisting ice-nucleating substances at concentrations as low as several mM. They are also effective to maintain supercooling, even when physical stimuli such as vibration are applied. These polyphenols are also found in various plants, and we are studying conditions for their industrial use. For example, the preservation of plant and animal cells and food in subzero temperatures and the prevention of frost damage to crops are interesting topics. Since the freezing-inhibition effect is affected by various factors, we are examining application possibilities, including the combination use of existing freezing inhibitors, and are trying to elucidate the mechanism of inhibiting ice nucleation activity.

Potential for social implementation

• ・Sub-zero refrigeration of drinking water, etc.
• ・Spraying agents for frost damage prevention
• ・Additives for cryopreservation of cells, etc.

Appealing points to industry and local governments

If it becomes possible to inhibit the freezing of water at sub-zero temperatures, it is expected to save the thermal energy required for freezing and thawing, and to inhibit the deterioration of quality caused by the growth of ice crystals. If the technology for stable freeze control is further developed, it is expected to expand its application to agriculture and industry. We are currently conducting experiments on spraying plants to prevent frost damage.