Encapsulated probiotics and nanoprobiotics - Biocompatible materials, processing technologies, and applications: A...

Probiotic efficacy is contingent upon delivering a sufficient number of viable cells to the site of action. However, industrial processing, storage, and gastrointestinal stresses frequently diminish survival rates below the ~10⁶-10⁷ CFU/g or mL typically required at the time of consumption. This review aims to provide a comprehensive overview of probiotic encapsulation-particularly micro- and nanoencapsulation-as a strategy to enhance viability and facilitate timely, site-specific release. We synthesized and analyzed existing literature on key encapsulating materials, including natural polysaccharides and proteins such as alginate, chitosan, pectin, starch, casein/whey, and selected synthetic pH-responsive polymers. We also examined major encapsulation techniques, including extrusion, emulsification, spray-drying, freeze-drying, electrospinning, and coacervation, with a focus on release mechanisms and compatibility with food matrices. Overall, encapsulation consistently improved resistance to acid, bile, oxygen, heat, and dehydration, often resulting in reduced viability losses compared to free cells, enhanced storage stability, and expanded applications in functional foods and novel biomedical delivery systems. Multilayer and nanoscale systems frequently provided additional protection and targeted release in the intestinal and colonic regions. However, performance is still dependent on specific strains and matrices, and challenges persist regarding process-induced damage, premature release, sensory and textural alterations, cost and scalability, and safety and regulatory standardization, particularly for nano-enabled formats. In conclusion, encapsulated probiotics represent a promising platform; however, future advancements should focus on the development of smart, stimuli-responsive materials, scalable automated manufacturing processes, and functional validation that extends beyond viable cell counts.