V. Micard et S. Guilbert, Thermal behavior of native and hydrophobized wheat gluten, gliadin and glutenin-rich fractions by modulated DSC, INT J BIO M, 27(3), 2000, pp. 229-236
Citations number
46
Categorie Soggetti
Biochemistry & Biophysics
Journal title
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
The glass transition temperature (T-g) of hydrophobized and native wheat gl
uten and its protein fractions, with water mass fraction from 0 to 0.2, was
studied using modulated differential scanning calorimetry. The T-g values
of unplasticized products were similar to 175 degrees C whatever the treatm
ent (hydrophobization) or the fraction tested, except for the gliadin-rich
fraction (162 degrees C). Experimental change in heat capacity at the glass
transition (Delta C-p) ranged from 0.32 to 0.50 J/g/degrees C depending on
the gluten fractions. The Gordon-Taylor fit of T-g evolution as a function
of water content showed that glutenin-rich fractions were more sensitive t
o water plasticization than the gliadin-rich fraction. The Kwei equation ga
ve better fit to experimental data and demonstrated that the water plastici
zation of gluten and its fractions is influenced by secondary interactions.
However, the application of the Couchman-Karasz equation without fitting p
redicts satisfactorily the plasticization of gluten proteins by water. (C)
2000 Elsevier Science B.V. All rights reserved.