Sucrose, maltodextrin and inulin efficacy as cryoprotectant, preservative and prebiotic – towards a freeze dried Lactobacillus plantarum topical probiotic

Probiotic formulations must contain the right strain(s) in sufficient numbers when administered to confer the desired health benefit. However, significant cell death can occur during freeze-drying and over storage. This study assesses various saccharides for their ability to protect Lactobacillus plantarum cells over freeze-drying and storage, as well as their potential to act as prebiotics. The cryoprotective potential of 10% (m/v) of skimmed milk, inulin, maltodextrin, and sucrose were investigated during freeze-drying. Storage was assessed over 12 weeks at 4 °C and room temperature. Improved cell survival over freeze drying was observed with all the saccharides. However, only maltodextrin and sucrose retained cell viability over storage at 4 °C. Overall, skimmed milk demonstrated the highest survival up to 91%. Despite good cryoprotectant performance, inulin provided the least protection over storage, with <1% cell survival. Prebiotic potential was determined through growth experiments with 2% (m/v) of the saccharides in glucose-free MRS. All saccharides supported cell growth, with sucrose performing best and inulin worst.