Model of the Continuous Prefermentation Process in Cheese Manufacture and Stability Analysis of Steady State

Abstract

The present study focused on the continuous prefermentation process affecting curd formation, and the subsequent pH changes in the first stage of cheese manufacture. Two typical continuous prefermentation systems in cheese manufacture were analyzed based on a kinetic model and the process control theory. A previously proposed mathematical model, which considers the effect of pH, adequately simulated the dynamic behavior of pH in the two continuous prefermentation processes. In the stability analysis of steady state using the Routh-Hurwitz criterion, we found that the continuous feed of a cheese starter culture prevented wash-out and stabilized the system independent of the fraction of seed feed rate. When no cheese starter culture was fed, the stabilities of steady states were dependent on the partial differentials of the maximum specific growth rate to lactic acid concentration. The feeding of cheese starter culture was effective to improve prefermentation process performance. PRACTICAL APPLICATIONSA proposed mathematical model, which considers the effect of pH, is available to optimize and control the prefermentation process in continuous cheese manufacture. The model that can predict cell dynamics and lactic acid 3 Corresponding