Correlation Between the Amount of Extracellular Polymeric Substances and the Survival Rate to Freeze-Drying of Probiotics

Abstract

To demonstrate that the amount of extracellular polymeric substances (EPS) and the freeze-dried viability of probiotics are correlated. Three strains of probiotics including Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Bifidobacterium bifidum were subjected to environmental challenges, such as temperature, pH, and carbon dioxide. The results indicated that the challenges could stimulate the EPS synthesis of the probiotics. The experimental correlation between the amount of synthesized EPS and the freeze-dried survival rate was also analyzed, and the viability of each of the three strains was represented by the following functions in which the equation of L. plantarum is y = - 0.0336x² + 2.7059x - 14.849 with R² = 0.9699, the B. bifidum's equation is y = - 0.0554x² + 2.6243x - 13.654 with R² = 0.9554, and the L. acidophilus's one was y = 0.0346x² + 0.5862x - 9.1339 with R² = 0.9733. This could be a new approach to determining the freeze-dried viability of probiotic strains based on the measured EPS content.