Efficacy of the incorporation between self-encapsulation and cryoprotectants on improving the freeze-dried survival of probiotic bacteria

Abstract Aims This study aimed to improve the viability of probiotic bacteria during freeze-drying by the combination of self-encapsulation and cryoprotectants. Methods and Results Lactiplantibacillus plantarum VAL6 and Lactobacillus acidophilus VAR1 were exposed to environmental stresses including temperature, pH and increased CO2 concentration before performing freeze-drying with the addition of cryoprotectants. The results proved that tested stresses can stimulate the bacteria to synthesize more extracellular polymeric substances to form self-encapsulation that increases their freeze-dried viability. In combination with cryoprotectants to form double-layered microencapsulation, L. plantarum VAL6 stressed at pH 3.5 in combination with whey protein isolate could achieve the highest Improving Cell Viability of 4361-fold, while L. acidophilus VAR1 stressed at 25oC in combination with alginate gave a maximum Improving Cell Viability of 73.33-fold. Conclusions The combination of self-encapsulation and cryoprotectants significantly improves the freeze-dried viability of probiotics. Significance and Impact of the Study This is the first report that uses environmental stress to stimulate extracellular polymeric substance synthesis for self-encapsulation formation combined with the addition of cryoprotectants to enhance the freeze-dried survival of probiotics. This could be a novel approach in improving the viability of probiotic strains for various applications.