Optimization of fermentation conditions for sourdough by three different lactic acid bacteria using response surface methodology

Abstract

This study aimed to investigate optimal fermentation conditions for sourdough by freeze-dried Lactobacillus curvatus N19, Weissella cibaria N9 and Lactobacillus brevis ED25 isolated from Turkish sourdough previously. The central composite rotational design was applied to the optimization of fermentation parameters (temperature and time). The fermentation was carried out under a simulated sourdough system and biomass concentration, total acidity, and lactic and acetic acid formation were chosen as response variables. Results showed that the models developed for all variables were significant (p < 0.05) and there was no lack of fit in any of quantifications (p > 0.05), indicating the suitability for representing the relationship between variables and factors. While both of the independent parameters were effect the response, fermentation time was the most significant factor influencing the response. The validation experiments using the optimized condition showed a good agreement between the experimental and predicted values except the lactic and acetic acid formation for W. cibaria N9. In conclusion, freeze-dried L. curvatus N19 can be used as a starter culture to sourdough fermentation for bread industry due to optimum fermentation conditions (29^oC temperature and 23h time).