Stability of Cloudy Apple Juice Colloidal Particles Modeled with the Extended DLVO Theory

GENOVESE, DIEGO B.; LOZANO, JORGE E.

Water Properties of Food, Pharmaceutical, and Biological Materials

CRC Taylor & Francis

Año: 2006; p. 289 - 300

  Cloudy apple juice is a polidisperse suspension of negatively charged particles. After the coarse material settles out by gravity, only small colloidal particles remain in suspension. The stability of this suspension depends on the interaction forces between particles. Classic DLVO theory only considers electrostatic repulsion and Van der Waals attraction forces. Parameters involved in the stability of cloudy apple juice were modified by treatment with a highly acid cationic resin, resulting in a reduction of the ionic strength, pH, and the magnitude of zeta-potential. However, cloud stability did not change significantly. Experimental and literature data were used to calculate colloidal interaction energies as a function of interparticle distance. In disagreement with experimental results, classic DLVO model predicted that cloudy juice should flocculate spontaneously after resin treatment. Its anomalous stability was explained in terms of non-DLVO repulsive interactions produced by hydration forces. Different mechanisms of particle hydration were proposed. Stability data was used to predict repulsive hydration energies with the extended DLVO theory.