The Iran-based teams tested how different chain lengths of inulin, either with or without chitosan, affected the survival of the probiotic Lactobacillus casei (L. casei). Those with both chitosan and long chain inulin survived best.
The team tested various combinations in a simulated gastrointestinal environment, measuring particle size and probiotic viability as performance markers.
The combinations with chitosan did not decrease in size, while those without were “significantly decreased”.
Previous studies looked mainly at either inulin or chitosan as a protective measure, and usually tested only one type of inulin, noted the researchers, led by Pegah Darjani, from Research Institute of Food Science and Technology (RIFST) in Iran.
Others have suggested that encapsulation with milk protein particles could increase probiotic stability, while a recent study on the potential for co-encapsulation of probiotic strains with omega-3s suggested synergistic health effects and benefits for delivery.
This recent study is the first time the prebiotic effect of inulin at different chain lengths has been tested with a coating material (chitosan), the team said.
For the combinations tested, the researchers incorporated L. casei with various inulin chain lengths (long, short and native), before microencapsulating them into alginate beads, either coated or uncoated with chitosan.
The samples were incubated at 37°C and the viability of the L. casei was measured at baseline, 60 minutes, and then 120 minutes.
“Chitosan coating provided the best protection for cells as compared to the incorporation of inulin into the alginate microcapsules (without coating),” the team said.
“Addition of different chain lengths of inulin (especially high performance [long chain] inulin) together with chitosan coating, significantly affected the survival of the probiotic bacteria during the gastro-intestinal fluid and bile salts tests, when compared with the alginate, alginate/inulin, alginate/chitosan beads and free cells.”
The team stressed future research is needed to refine encapsulation techniques used in the study, and to test the combinations in animals.
Other experts agree protective coatings are an interesting prospect, including Pharmachem’s director of business development who recently told sister site NutraIngredients-USA that the future of probiotics is in developing new delivery forms and encapsulation technologies.
Source: LWT - Food Science and Technology
Volume 73, November 2016, Pages 162–167, doi: 10.1016/j.lwt.2016.05.032
“Influence of prebiotic and coating materials on morphology and survival of a probiotic strain of Lactobacillus casei exposed to simulated gastrointestinal conditions”
Authors: Pegah Darjania, et al