Cla. Berli et al., Heat-induced phenomena in soy protein suspensions. Rheometric data and theoretical interpretation, J AGR FOOD, 47(3), 1999, pp. 893-900
Heat-induced aggregation of soy proteins in aqueous suspensions was studied
through cone and plate rheometry for two different heating conditions. The
rheometric data obtained covered the temperature range from 20 degrees C (
stable colloidal suspension) to similar to 90 degrees C (onset of network f
ormation). Calorimetric data for the soy protein samples were also obtained
to evaluate the degree of protein denaturation in the rheometric cell. Hea
t-induced transitions in soy globulins, such as dissociation, denaturation,
and aggregation, were analyzed in relation to the rheological response of
the suspension. The viscosity of the stable colloidal suspension satisfies
the Cross model. A viscosity equation for the aggregating suspension was al
so derived by considering the fractal structure of the particle clusters an
d the Brownian aggregation mechanism. This equation is suitable to describe
the experimental viscosity data.