title: Thermodynamic analysis of sol-gel transition of gelatin in terms of water activity in various solutions.
abstract: Sol-gel transition of gelatin was analyzed as a multisite stoichiometric reaction of a gelatin molecule with water and solute molecules. The equilibrium sol-gel transition temperature, Tt , was estimated from the average of gelation and melting temperature measured by differential scanning calorimetry. From Tt and the melting enthalpy, ΔHsol , the equilibrium sol-to-gel ratio was estimated by the van't Hoff equation. The reciprocal form of the Wyman-Tanford equation, which describes the sol-to-gel ratio as a function of water activity, was successfully applied to obtain a good linear relationship. From this analysis, the role of water activity on the sol-gel transition of gelatin was clearly explained and the contributions of hydration and solute binding to gelatin molecules were separately discussed in sol-gel transition. The general solution for the free energy for gel-stabilization in various solutions was obtained as a simple function of solute concentration.
authors.affiliation: Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
authors.forename: Osato
authors.initials: O
authors.lastname: Miyawaki
authors.affiliation: Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Omote
authors.affiliation: Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Matsuhira
mesh_terms: D005780:Gelatin / Q000737:chemistry*; D005782:Gels; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D005782:Gels; D012996:Solutions; D014867:Water; D005780:Gelatin
keywords: free energy for gel-stabilization; gelatin; hydration; sol-gel transition; solute binding; water activity