Encapsulation of Bifidobacterium pseudocatenulatum G7 in gastroprotective microgels: Improvement of the bacterial viability under simulated gastrointestinal conditions

Abstract

The oral delivery of probiotics to the colon is often challenging because probiotics tend to lose viability when exposed to the harsh conditions in the upper gastrointestinal tract, such as the highly acidic gastric fluids. Properly designed encapsulation technologies can be used to protect probiotics during their transit through the human gut. In this study, an anaerobic probiotic (Bifidobacterium pseudocatenulatum G7 or BPG7) was encapsulated within alginate microgels that also contained antacid agents to control their internal pH within the stomach. Probiotic-loaded microgels were exposed to a simulated gastrointestinal tract (GIT) model to establish the impact of gastric and small intestinal conditions on their physicochemical properties and cell viability. In the absence of antacids, no live probiotic cells were detected in the microgels after exposure to gastrointestinal conditions. Conversely, in the presence of antacids, there was only a 1.5 log CFU decrease in cell viability after incubation in simulated gastric fluids for 2 h. Subsequently, after the antacid microgels were incubated in simulated intestinal fluids, considerable amount of viable probiotic cells were still detected when CaCO3 was used as an antacid but not when Mg(OH)2 was used. Overall, these results indicated that alginate microgels containing CaCO3 as an antacid were efficient at protecting the probiotic during passage through the upper GIT. This novel encapsulation technology utilizing all food grade materials may be useful for the oral delivery of probiotics to the gut in the form of functional foods or supplements.