title: Dynamics of Uncrystallized Water, Ice, and Hydrated Protein in Partially Crystallized Gelatin-Water Mixtures Studied by Broadband Dielectric Spectroscopy.
abstract: The glass transition of partially crystallized gelatin-water mixtures was investigated using broadband dielectric spectroscopy (BDS) over a wide range of frequencies (10 mHz to 10 MHz), temperatures (113-298 K), and concentrations (10-45 wt %). Three dielectric relaxation processes (processes I, II, and III) were clearly observed. Processes I, II, and III originate from uncrystallized water (UCW) in the hydration shells of gelatin, ice, and hydrated gelatin, respectively. A dynamic crossover, called the Arrhenius to non-Arrhenius transition of UCW, was observed at the glass transition temperature of the relaxation process of hydrated gelatin for all mixtures. The amount of UCW increases with increasing gelatin content. However, above 35 wt % gelatin, the amount of UCW became more dependent on the gelatin concentration. This increase in UCW causes a decrease in the glass transition temperature of the cooperative motion of gelatin and UCW, which appears to result from a change in the aggregation structure of gelatin in the mixture at a gelatin concentration of approximately 35 wt %. The temperature dependence of the relaxation time of process II has nearly the same activation energy as pure ice made by slow crystallization of ice Ih. This implies that process II originates from the dynamics of slowly crystallized ice Ih.
authors.affiliation: Department of Physics, Graduate School of Science, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.|Micro/Nano Technology Center, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.
authors.forename: Kaito
authors.identifier: 0000-0002-2365-650X
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Department of Physics, National Technical University of Athens , Zografou Campus, 15780 Athens, Greece.
authors.forename: Anna
authors.initials: A
authors.lastname: Panagopoulou
authors.affiliation: Department of Physics, Graduate School of Science, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.|Micro/Nano Technology Center, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.
authors.forename: Rio
authors.initials: R
authors.lastname: Kita
authors.affiliation: Department of Physics, Graduate School of Science, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Shinyashiki
authors.affiliation: Department of Physics, Graduate School of Science, Tokai University , 4-1-1 Kitakaname, Hiratuka-shi, Kanagawa, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yagihara
authors.affiliation: Department of Physics, National Technical University of Athens , Zografou Campus, 15780 Athens, Greece.
authors.forename: Apostolos
authors.initials: A
authors.lastname: Kyritsis
authors.affiliation: Department of Physics, National Technical University of Athens , Zografou Campus, 15780 Athens, Greece.
authors.forename: Polycarpos
authors.initials: P
authors.lastname: Pissis
mesh_terms: D003460:Crystallization; D058266:Dielectric Spectroscopy; D005780:Gelatin / Q000737:chemistry*; D007053:Ice; D056004:Molecular Dynamics Simulation; D014867:Water / Q000737:chemistry*
chemical_list: D007053:Ice; D014867:Water; D005780:Gelatin