Statistical Modelling and Optimization of Lactic Acid Fermentation in the Presence of Anionic Clay and Ultrasonic Field

摘要

Statistical modelling and optimization of acid lactic fermentation of milk inoculated with lactic bacteria, in the presence of anionic clay and ultrasonic field, was performed. A 3(3) factorial experiment was selected in order to correlate the lactic acid concentration in the fermentation medium (process response) to process factors, i.e., fermentation temperature (38-48 degrees C), clay/milk ratio (1-8 g/L), and fermentation time (2-4 hr). 27 experimental runs were performed at 3 factor levels (low, middle, and high). The factorial statistical model consisted of a second order polynomial regression correlation between process response and factors. This regression relationship was applied to optimize the fermentation process. Optimal values of factors are close to the middle level of temperature (43 degrees C), high level of clay/milk ratio (8 g/L), and low level of fermentation time (2 hr).