Viability Preservation of Probiotic Bacteria Encapsulated in Pectin-Reinforced pH-Responsive Composite Alginate...

Preserving probiotics that offer mitigation of a range of digestive disorders and remedies for dysbiosis when consumed in sufficient quantities is a significant challenge in the development of medicinal products and nutritional supplements. This investigation illustrates the creation of polysaccharide-reinforced composite hydrogels that encapsulate planktonic and biofilm type probiotic cells of Alkalihalobacillus clausii and Lactobacillus plantarum. The hydrogels were prepared using ionic gelation method and response surface optimization to enhance encapsulation efficiency and cell viability against the stresses (e.g., heating, freezing, varying storage temperatures, long-term storage, and exposure to acidic and alkaline environments) typically encountered during product processing and gastrointestinal transit. The results indicate that biofilm-loaded hydrogels demonstrate superior acid resistance and better long-term viability, along with higher thermotolerance when subjected to dry heat treatment at temperatures up to 70 °C. However, their viability declines at higher temperatures (> 80 °C) even with brief exposures. Although the release of biofilm type cells in simulated intestinal fluid is lower than that of planktonic cells, the biofilm cells maintain superior viability over a longer time period. Furthermore, the extract and secretome of both the probiotic bacteria exhibit a significant antibacterial effect against pathogenic Escherichia coli (in both planktonic and biofilm form). These findings strongly suggest that pectin supplemented alginate beads can serve as a protective synbiotic transport system for these aforementioned probiotic strains.