Grounds for winning the 2014 Society Award ofthe Japan Society for Cryobiology and Cryotechnology
CryobiologicalandCryotechnologicalResearchfromtheStandpointof

Physicochemistry of Water
By Dr. Osato Miyawaki (Professor of Ishikawa Prefectural University)

Dr. Osato Miyawaki graduated and received Dr. degree from the University ofTokyo (UT) in 1974. After that, his academic carrier started from an assistant professor
in UT, a visiting assistant professor in University of Pittsburgh, and then he came backto UT as an associate professor in 1988. In 2005, he became a full professor in Ishikawa
Prefectural University. He joined our society in 1985. Since then, he was activelyinvolved in the various activities of the society though his many academic contributions
as well as managements as a director, an editor-in-chief, and the president.
Dr. Miyawaki proposed a theory that explains the ice crystal size (dP) formed infrozen food to be inversely proportional to the advance speed of the freezing front of ice(u) with a proportional constant in the order of water diffusion coefficient (DW). This is
an important finding to analyze and control ice crystal structure in frozen food.
In the freezing of living cells, an extracellular freezing generally occurs prior to
an intracellular freezing, which causes cell dehydration through the freeze-induced
osmotic dehydration. As the intracellular freezing causes a fatal damage on the cell, therapid dehydration is important during the extracellular freezing stage. Dr. Miyawaki
found out the importance of the combined parameter LP/dP	  (LP, water permeability ofmembrane; dP, cell size) as a parameter to determine the dehydration rate of cells. He
measured and compared this parameter among microorganism, animal, and plant cells
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to find out that the plant cell has the lowest LP/dP value among those. This explains thedifficulty in the freezing preservation of plant cells compared with other cells.
Freeze concentration has been known as the best method for high-quality
concentrationofliquidfood.

However,theconventionalmethod,suspension

crystallization, is very complex and highly expensive so that this method is not widelyused in practice. On the contrary, Dr. Miyawaki proposed a new method, progressive
freeze-concentration, in which a single ice crystal is formed on the cooling plate. Thismethod makes the system much simpler so that a substantial cost reduction is expectedin freeze concentration. A project is now going on to apply this method in practice.
He, recently, proposes a new theory on the role of hydration in protein stability.
In this approach, the unfolding ratio of a protein is directly correlated to the water
activity (aW) of the system. This shows the important role of hydrogen-bondings among
amino acid residues as well as the hydrophorbic interaction in protein stability. This
clearly explains the important role of aW in protein stability, which has been neglected
for the long time in the literature. This theory is expected to bring about a new
break-through in the basic understanding of the marginal stability of proteins.
Thus, Dr. Miyawaki made a remarkable contribution to our society through his
original activities on cryobiological and cryotechnological research from the standpointof physicochemistry of water. Therefore, he deserves the 2014 Society Award of theJapan Society for Cryobiology and Cryotechnology.

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