pH CONTROL DURING CONTINUOUS PREFERMENTATION OF YOGURT STARTER CULTURE BY STRAINS STREPTOCOCCUS THERMOPHILUS 13A AND LACTOBACILLUS BULGARICUS 2-11

摘要

A pH indirect control algorithm for the continuous prefermentation of yogurt starter culture by strains Lactobacillus bulgaricus 2-11 and Streptococcus thermophilus 13A is proposed. A linear relationship between lactose concentration and pH value in the reactor is determined. On this basis, a new model of continuous mode of cultivation is proposed that includes pH dynamical equation. A software sensor of lactose consumption rate is derived. The obtained estimates are used for pH control derivation by lactose feeding. The results of simulation investigations show good performance of the proposed control algorithm.