Effect of homogenisation on bead size and survival of encapsulated probiotic bacteria

This study investigated homogenisation techniques for reducing the size of calcium alginate beads during the microencapsulation of Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus and Bifidobacterium longum. Bead sizes were reduced using three homogenisation techniques including Ultra-Turrax benchtop homogeniser, Avestin Inc. piston homogeniser and Silverson mixer for various durations, number of passes and pressures. The survival of probiotic organisms during homogenisation was also investigated. The smallest beads (39.2 mu m) were created using the Ultra-Turrax benchtop homogeniser at 13500 rpm for 4 min. There was a significant reduction in the survival of each organism (< 5.5%) using the Silverson mixer. However, homogenisation using Ultra-Turrax and Avestin Inc. homogenisers resulted in better survival at 64.4% and 47.7%, respectively. Overall, homogenisation reduced size of beads containing viable probiotic organisms during microencapsulation. (c) 2007 Elsevier Ltd. All rights reserved.