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.

Camouflaging attenuated Salmonella by cryo-shocked macrophages for tumor-targeted therapy

“…This is understandable because bacteria can achieve cold-temperature resistance by regulating membrane composition and cold shock protein expression. 31 , 32 Transmission electron microscopy (TEM) revealed intact strains within the cells, including live macrophages and cryo-shocked macrophages (Fig. 2c ).…”