Effects of lyoprotectant and encapsulated Lactobacillus acidophilus KBL409 on freeze-drying and storage stability

The purpose of this study was to optimize the encapsulated formulation and freeze-drying conditions of Lactobacillus acidophilus KBL409 to improve shelf-life. The optimum freeze-drying conditions was 8% sucrose as a lyoprotectant at -30 degrees C. In addition, the free, alginate-encapsulated (Al-), and alginate/chitosan-encapsulated (Al/Chi-) L. acidophilus KBL409 with or without sucrose were prepared and evaluated for the simulated gastrointestinal (SGI) tract, moisture characteristics, and storage stability. The freeze-dried Al/Chi-cells with sucrose displayed the highest survival rate of 0.14% in the SGI tract (p < 0.05). The cells showed sigmoidal sorption isotherms and moisture content of 0.084 kg water/kg solid for Brunauer-Emmett-Teller-monolayer. At 4 C/60% RH, the glass transition temperature was 12.55 degrees C, which allowed for 12-week period of glassy state and the highest storage viability of 22.35%. In conclusion, the viability of Lactobacillus acidophilus KBL409 faces distinct challenges for freeze-drying and storage, and encapsulation with lyoprotectant affects various stability and quality attributes of microorganisms.

Automated summary

The aim of this study was to improve the shelf-life of Lactobacillus acidophilus KBL409 by optimizing its encapsulated formulation and freeze-drying conditions. The optimal freeze-drying conditions were determined to be 8% sucrose as a lyoprotectant at -30°C. Various encapsulated forms of L. acidophilus KBL409, including free, alginate-encapsulated (Al-), and alginate/chitosan-encapsulated (Al/Chi-), with or without sucrose, were prepared and evaluated for simulated gastrointestinal (SGI) tract, moisture characteristics, and storage stability. The results showed that the freeze-dried Al/Chi-cells with sucrose had the highest survival rate in the SGI tract and exhibited favorable moisture content and stability during storage.