Filtration Behavior during Soymilk Separation Process

Abstract

In this study, constant-pressure filtration was carried out to examine the blocking mechanisms during soymilk separation. In the filtration experiments, okara was deposited on filter paper of the membrane module in view of the separation process in soymilk. We found that a standard blocking model could be applied to explain the filtration behavior of soymilk by the okara layer at temperatures between 70 and 90°C. The initial filtration rate monotonically increased depending on decreasing viscosity, but the blocking coefficient decreased as the soymilk temperature increased below 85°C, but increased at 90°C. In order to clarify the temperature dependence of the dispersion states of soymilk particles, we determined the particle size distribution and ζ-potential of soymilk particles. The temperature dependence of the blocking coefficient was related to the average size of particles in soymilk. Therefore, the behavior of blocking in the okara layer would be considered the main issue in the soymilk separation process.