title: Glass transition and enthalpy relaxation of polyphosphate compounds.
abstract: The glass transition behaviour of polyphosphate compounds such as di- and tri- polyphosphates used as food additives and ATP, ADP existing in biosystems, were investigated by using DSC. From the DSC heating curves of the frozen solutions, the glass transition temperatures of the maximum freeze concentrated solutions, Tg', were determined. It was found that Tg's for polyphosphates are relatively high. The lyophilized tripolyphosphates, ATP and ADP also showed the glass transition at a relatively high temperature, depending on the moisture content. In addition, the enthalpy relaxation behaviour of glassy ATP and ADP was examined and analyzed by using the Kohlrausch-Williams-Watts (KWW) and the Vogel-Fulcher-Tammann (VFT) equations. Judging from the parameters of the KWW and VFT equations, the amorphous states of ATP and ADP were suggested to be more fragile than trehalose and sucrose.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Fisheries, 4-5-7 Konan, Minato-ku, 108-8477, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawai
authors.forename: Toru Suzuki
authors.initials: TS
authors.lastname: Suzuki
authors.forename: Rikuo
authors.initials: R
authors.lastname: Takai
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005612:Freeze Drying; D005615:Freezing; D005898:Glass / Q000737:chemistry*; D006358:Hot Temperature; D011122:Polyphosphates / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D011122:Polyphosphates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate