J024031 Inhibition of Ice Nucleation by Polyphenol Compounds

Abstract

Antifreeze proteins (AFPs) and several synthetic polymers are known as anti-ice nuclei (anti-IN), which inactivate ice nuclei (IN) in water and thus inhibit heterogeneous ice nucleation catalyzed by IN. Recently, it has been found that several types of polyphenol compounds also inhibit heterogeneous ice nucleation. In this study, ice nucleation catalyzed by silver iodide (Agl) particles, which are typical inorganic IN, in emulsified solutions of five different polyphenol compounds (a-oligoglucosyl quercetin 3-O-β-D-glucopyranoside (Q3(Glc)n), epigallocatechin gallate (EGCG), tea catechin, tannic acid, and oligonol) was investigated experimentally. Results showed that the ice nucleating activity of Agl was inactivated by all the polyphenols used here. For Q3(Glc)n and EGCG solutions, in the majority of the emulsified droplets, ice nucleation occurred within a narrow temperature range between -17 and -20℃. On the contrary, for tea catechin, tannic acid, and oligonol solutions, ice nucleation occurred within relatively wide temperature range between -17 and -38 ℃. The highest ice nucleation temperatures in the emulsified droplets of the polyphenol solutions were considerably lower than those of AFP and synthetic polymer solutions. Especially, the highest ice nucleation temperature for oligonol solution was -19.4 ℃. Such anti-ice nucleating activities of the polyphenols available at relatively high temperatures would be promising for practical applications in various fields.