Abstract
Effect of hydration on various functions of proteins and food properties was analyzed in consideration of water potential (water activity). From the thermodynamic analysis, the stabilizing effects of sugars in the thermal unfolding of lysozyme and α-chymotripsinogen A were explained by the indirect effect of water potential while the destabilizing effects of urea and formamide were explained only by the direct interaction of these solutes to the protein. Similar phenomena were observed in the effects of solutes on protein thermal stability, enzyme-substrate complex formation, and sol-gel transition, suggesting the existence of a common mechanism among these processes through the hydration of proteins.
