Microencapsulation of indigenous probiotic lactobacillus plantarum dad-13 by spray and freeze-drying: Strain-dependent effect and its antibacterial property

Abstract

Lactobacillus plantarum Dad-13 is a potential probiotic candidate, and microencapsulation is the method for extending its shelf-life. Furthermore, spray or freeze-drying is a common method for microencapsulation, and its effect on the stability of probiotic is strain-dependent. This research was aimed to evaluate the strain-dependent effect of probiotic microencapsulation and to choose a suitable method for further research. In this research, for strain-dependent analysis, L. plantarum strain Mut-7 was used as a comparison. Probiotics were encapsulated with 10% (w/v) skim milk and 1 % (w/v) sucrose as wall material by spray and freeze-drying method. The obtained probiotics powder was then analyzed for physicochemical, sublethal injury and stability during storage. Freeze-dried L. plantarum Dad-13 was than analyze the antibacterial activity against pathogenic bacteria. The results showed that aw, color and particle diameter were significantly different between the spray and freeze-dried probiotics. Hence, the microstructure of spray-dried microcapsule was spherical and wrinkle, while the freeze-dried microcapsule was porous. However, the viable cell of freeze-dried probiotic was significantly higher and more stable during eight weeks of storages. From both strains, we found that there was no strain-dependent effect on viable cells after the drying method. Thus, we deduced that freeze-drying was the suitable method for microencapsulation L. plantarum strain Dad-13, considering the freeze-dried L. plantarum Dad-13 still had antibacterial activity.