Soybean Protein Dispersions at Acidic pH. Thermal and Rheological Properties

MARIA CECILIA PUPPO; AÑÓN, M. C.

Journal of Food Science

ACS Publications

Año: 1999 vol. 64 p. 50 - 56

0022-1147

The influence of pH, protein concentration, and ionic strength, on rheological properties of thermally treated acidic soy protein dispersions, was studied. Structural changes due to pH effect and thermal treatment were analized. DSC-thermograms at pH 3.5 showed a shoulder at 74.1160.168C that could be attributed to both b-conglycinin and the hexameric form of glycinin; and a peak at 81.88+/-0.29 ºC corresponding to 11S dodecameric form. At pH 2.75 one endotherm corresponded to denaturation of b-conglycinin. The acidic dispersions presented pseudoplastic behavior with happ values higher than those at pH 8.0. At pH 3.50 the apparent viscosity was higher than at pH 2.75. The maximum viscoelasticiy was obtained with addition of 0.1 and 0.25M NaCl in the dispersions of pH 3.50 and 2.75, respectively. The increase in viscoelasticity was enhanced by the formation of 11S native fraction dimers.