Influence of Acidity Regulators on the Stability of a Soymilk Colloidal Dispersion System

Abstract

To elucidate the influence of acidity regulators on stability using a soymilk colloidal dispersion system, a viscous model was constructed, and its effectiveness was verified. When the pH of soymilk was reduced using ascorbic acid, the apparent viscosity of all soymilk increased significantly at approximately pH 5.8-5.9; this was found to be a universal phenomenon in the soymilk colloidal dispersion system. When the pH decreased after addition of six types of acidity regulators to soymilk, the apparent viscosity behaviors of the samples were similar. Assuming that the bulkiness of the aggregate was proportional to the hydrogen ion concentration in the high pH range, calculations were made by applying the extended equation obtained from the viscosity equation of Einstein and the Krieger-Dougherty equation. A negative correlation was confirmed with the parameter h_c representing the degree of bulkiness of the aggregate and the parameter K_c representing the degree of filling state of the gigantic aggregate. Moreover, the macroscopic aggregation behavior was similar, even if the internal structure of the isolated aggregates differed depending on differences in the crosslinking mechanism. Because of the correlations between parameters, this system for soymilk processing may have industrial applications.