Microencapsulation of probiotics in chitosan-coated alginate/gellan gum: Optimization for viability and stability enhancement

Abstract

Recently, the benefits of probiotics have significantly expanded their application in functional food products. However, preserving their viability and stability throughout gastrointestinal transit and storage is challenging. This study aims to address these issues by encapsulating probiotics in chitosan-coated alginate/gellan gum microcapsules using a vibrational nozzle-assisted ionic gelation approach. The encapsulation process was successfully optimized using the response surface methodology. The optimum conditions were applied (gellan gum concentration of 0.6%, CaCl2 concentration of 1.61%, and flow rate of 9.84 mL/min), resulting in a high encapsulation efficiency (97.35%) and tolerance to simulated gastric fluid (7.13 log CFU/g). Thereafter, the physicochemical properties of the optimized microcapsules were evaluated. The microcapsules exhibited a uniform size distribution, averaging approximately 500–600 μm in diameter. The incorporation of the gellan gum with alginate resulted in a dense structure. All treated microcapsules released probiotics at approximately 7.06 log CFU/g after 6 h of immersion in an intestinal fluid following the Korsmeyer–Peppas release mechanism. Furthermore, storage experiment revealed that the optimized microcapsules could maintain above 8 log CFU/g of probiotics after 30 days. Our study offers a potential encapsulation system for probiotic applications in food products, paving a new path for the development of functional ingredients.