A differential scanning calorimetry study of wheat proteins

Thermal properties of wheat proteins were studied by differential scanning calorimetry (DSC). In order to assess the endothermic peaks, protein samples were heated with different water contents. At very low water content it was possible to register the protein endotherms at 50 degreesC for albumins and globulins, and 58 degreesC for gliadins, whereas two endothermic peaks at 64 and 84 degreesC were assigned to glutenins. The enthalpies of the protein transitions were very small for albumins, globulins, and gliadins, but high enthalpies (11.47 and 14.43 J/g) were obtained in the case of glutenins, suggesting a more ordered structure of these proteins. Reversibility of the glutenin denaturation was demonstrated by DSC; the successive heating-cooling cycles showed a shift in the endotherm peaks to higher temperatures and also higher enthalpies were required after each cycle.