Diethanolamine and triethanolamine were selected among several low and high
molecular weight polyols and amines tested as potential plasticizers of wh
eat gluten film. In comparison with glycerol, their use did not significant
ly affect the solubility in water, the opacity of the film (both increased
very slightly) and the water vapor barrier properties. However, significant
changes in mechanical properties were observed, i.e., increase in extensib
ility and elasticity. At 58% relative humidity (RH) and 20 g/100 g dry matt
er of di or triethanolamine, the elongation was five times higher than film
plasticized with glycerol. At 98% RH, water appeared to compete with the a
mines to act as the plasticizer. Dynamic mechanical thermal analyses showed
a glass transition temperature similar to that of the glycerol plasticized
film. However, the observed broadening of thermal transition and the decre
ase in height of tan 6 peak in the presence of amines, were related to diff
erences in the type of the interactions with the proteins and to the basici
ty of the amino compounds. (C) 2001 Elsevier Science Ltd. All rights reserv
ed.