2.3. Acidification kinetics of microencapsulated bacteria
Free and encapsulated cells of L. casei and B. lactis were cultivated in MRS-broth to determine if the encapsulated cells were still metabolically active and if nutrients and metabolites could permeate bead wall. To obtain the time needed for free and encapsulated cells to acidify MRS-broth medium, (2.5 ± 0.1) 106 (CFU g 1) of free cells and (2.5 ± 0.3) 106 (CFU g 1) of encapsulated cells (in beads) were inoculated into the 100 mL MRS-broth medium and incubated at 37 C for 56 h. The pH values and optical density (OD) at 525.2 nm were measured every 4 h (Homayouni, Ehsani, Azizi, Razavi, & Yarmand, 2008b).