The optimization of spray drying process of Lactobacillus reuteri

• Response surface methodology is a useful tool for optimizing the spray drying process.
• Our study provides a technical reference for better industrial production.
• The optimized spray drying process yields higher numbers of viable bacteria.

This study optimized spray drying process of Lactobacillus reuteri (L. reuteri) and increased the survival rate of bacteria using the optimized method. Experiments were designed with quadratic orthogonal rotation combination design. Effects of independent variables on response value were analyzed by response surface methodology. The results showed that the spray drying process was optimized as follows: outlet temperature was 90 °C, inlet temperature was 140 °C, skim milk concentration was 20% (w/v), feeding speed was 1200 mL/h. The effect of optimized process was verified by showing that the mean survival rate was 72.50%, which was basically consistent with the predicted value (74.91%). This study showed that quadratic orthogonal rotation combination design and response surface methodology were useful tools for optimizing the spray drying process for L. reuteri DYF5. In addition, L. reuteri preparations produced by optimized spray drying process yielded higher numbers of viable bacteria. Thus, our finding provided a technical reference for industrial production.