Enhancing Stability and Mucoadhesive Properties of Porous Starch Through Chitosan Surface Modification for Potential Oral Mucosal Probiotic Delivery

Probiotics have great potential in preventing and treating oral diseases; however, they are prone to low survival rates or poor biological activity during production, storage, and application. Moreover, their insufficient attachment time on the oral surface may reduce their efficacy. Therefore, we developed chitosan-modified porous starch (CMPS) microcapsules to overcome these limitations. The chitosan modification improved the oil and water absorption capacity of PS and increased thermal decomposition temperature, enhancing heat resistance. In addition, the survival rate of CMPS-coated Streptococcus salivarius K12 after freeze-drying increased up to 98.82%. In contrast, the number of viable bacteria following heat treatment at 70 °C for 20 min decreased by merely 0.23 log colony-forming units per gram. Furthermore, survival rate was significantly improved under long-term storage, even at 26 weeks, and the number of viable bacteria remained above 8.0 log colony-forming units per gram at both 4 °C and 25 °C. In a mucosal adhesion assay, chitosan significantly increased the adhesion rate of S. salivarius K12 to 47.96% after 30 min of saliva rinsing. It also exhibited efficient release in simulated saliva fluid, reaching 97.10%. Thus, we identified CMPS as a novel oral delivery vehicle for oral mucosal probiotics that protects against adverse environmental influences and maintains storage stability. Additionally, it promotes colonization on the mucosal surface, providing a new method for oral probiotic application.