Investigation of Lactobacillus plantarum and Phytosterol co-encapsulation by complex coacervation

Co-encapsulation of more than one core material in a single encapsulation system may increase the bioactivity of individual components. Whey protein isolate (WPI) and Gum Arabic (GA) were used as wall material to encapsulate probiotic bacteria Lactobacillus plantarum (P) alone or in combination with phytosterol (Ph) by complex coacervation method. The liquid microcapsules WPI-P-GA and WPI-P-Ph-GA were transferred to the powder using spray and freeze-drying to produce solid microcapsules. Results showed that the cell viability of L.plantarum in both liquid and dried microcapsules (freeze and spray drying) were much better in the presence of phytosterol (WPI-P-Ph-GA) than the absence of it (WP-Ph-GA) and the viability of L.plantarum in spray-dried solid microcapsules was better in comparison to the freeze-dried microcapsules during the storage time (60 days). Encapsulation efficiency in spray dryer was significantly (p > 0.05) higher than freeze dryer. The microcapsules were characterized in terms of Size, Zeta Potential, and poly dispersity index (PDI). The particle size of WPI-GA and WPI-Ph-GA were 196.2±13.72 and 366.5±0.56 nm respectively. Electrostatic interaction and formation of coacervates were confirmed by Fourier Transform Infra-Red (FTIR) spectra. Scanning electron microscopy (SEM) analysis showed that microcapsules dried by freeze dryer had a porous morphology and did not have any particular shape but microcapsules that dried by spray dryer showed the quasi-spherical configuration and had a wrinkled surface. X-ray pattern of co-microencapsulated identified that microcapsules dried by freeze-dryer had an amorphous structure compared to spray-dried ones.