title: Effects of thermal denaturation on the solid-state structure and molecular mobility of glycinin.
abstract: The effects of moisture and thermal denaturation on the solid-state structure and molecular mobility of soy glycinin powder were investigated using multiple techniques that probe over a range of length and time scales. In native glycinin, increased moisture resulted in a decrease in both the glass transition temperature and the denaturation temperature. The sensitivity of the glass transition temperature to moisture is shown to follow the Gordon-Taylor equation, while the sensitivity of the denaturation temperature to moisture is modeled using Flory's melting point depression theory. While denaturation resulted in a loss of long-range order, the principal conformational structures as detected by infrared are maintained. The temperature range over which the glass to rubber transition occurred was extended on the high temperature side, leading to an increase in the midpoint glass transition temperature and suggesting that the amorphous regions of the newly disordered protein are less mobile. (13)C NMR results supported this hypothesis.
authors.affiliation: CSIRO Food Futures Flagship, North Ryde, NSW 2113, Australia. mickey.huson@csiro.au
authors.forename: Mickey G
authors.initials: MG
authors.lastname: Huson
authors.forename: Ekaterina V
authors.initials: EV
authors.lastname: Strounina
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Kealley
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Rout
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Church
authors.forename: Ingrid A M
authors.initials: IA
authors.lastname: Appelqvist
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gidley
authors.forename: Elliot P
authors.initials: EP
authors.lastname: Gilbert
mesh_terms: D002152:Calorimetry, Differential Scanning; D005898:Glass / Q000737:chemistry; D005916:Globulins / Q000737:chemistry* / Q000378:metabolism; D006813:Humidity; D009682:Magnetic Resonance Spectroscopy; D009038:Motion; D011487:Protein Conformation; D011489:Protein Denaturation; D012996:Solutions; D030262:Soybean Proteins / Q000737:chemistry* / Q000378:metabolism; D013025:Glycine max / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D005916:Globulins; D012996:Solutions; D030262:Soybean Proteins; C011474:glycinin