Temperature, effect cereal proteins

Xie, F., Dowel, F.E., and Sun, X.S. 2004. Using visible and near infrared reflectance spectroscopy and differential scanning calorimetry to study starch, protein and temperature effects on bread stahng. Cereal Chem. 81(2) 249-254. 

The decrease in expansion seems to occur at moisture levels above 30°/o moisture for both cereal (starch-based) polymer systems, and protein (soy grits). This corresponds to a point on their adsorption curves where water activity rises rapidly with added moisture that is, at a level where the water added to a mix has little effect on primary hydration of polymers, but behaves as a diluent. In mechanical terms, this may be explained by proposing that at above levels of 25°/o-30% water plasticisation of the polymers is complete, and further added water acts as a lubricant, reducing the shear-induced temperature rise and particle damage necessary for the formation of homogeneous melts. 

Much work has also been carried out on non-cereal plant proteins. Solid-state H and 2H NMR transverse relaxation measurements were used to investigate the effect of hydration on the plasticization of vicilin, legumin, and albumin fractions from peas.81 Their behaviour indicated that the plasticization of the globular legume proteins is considerably less than that found before for the linear barley protein C-hordein. The effects of microbial transglutaminase treatment on soy protein samples have been studied by H and solid-state 13C NMR spectroscopy, and its relation to the glass transition temperature was examined.82-83... 

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