title: Protection of bifidobacteria encapsulated in polysaccharide-protein gel beads against gastric juice and bile.
abstract: Bifidobacterium cells were encapsulated in a mixed gel composed of alginate, pectin, and whey proteins. Two kinds of capsules were obtained: gel beads without membranes and gel beads with two membranes formed by the transacylation reaction. In vitro studies were carried out to determine the effects of simulated gastric pH and bile salts on the survival of free and encapsulated Bifidobacterium bifidum. The protective effects of gel beads without membranes and gel beads coated with two membranes formed by the transacylation reaction were evaluated. After 1 h in an acidic solution (pH 2.5), the free-cell counts decreased by 4.75 log units, compared with a <1-log decrease for entrapped cells. The free cells did not survive after 2 h of incubation at pH 2.5, while immobilized-cell counts decreased by about 2 log units. After incubation (1 or 3 h) in 2 and 4% bile salt solutions, the bifidobacterium mortality level for membrane-free gel beads (4 to 7 log units) was higher than that for free cells (2 to 3 log units). However, counts of bifidobacteria immobilized in membrane-coated gel beads decreased by <2 log units. Cell encapsulation in membrane-coated protein-polysaccharide gel beads could be used to increase the survival of healthy probiotic bacteria during their transit through the gastrointestinal tract.
authors: Centre de Recherche en Sciences et Technologie du Lait STELA, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, Canada G1K 7P4.
authors: Daniel
authors: D
authors: Guérin
authors: Jean-Christophe
authors: JC
authors: Vuillemard
authors: Muriel
authors: M
authors: Subirade
mesh_terms: D000464:Alginates; D001644:Bifidobacterium / Q000187:drug effects / Q000254:growth & development*; D001647:Bile Acids and Salts / Q000494:pharmacology*; D015169:Colony Count, Microbial; D005750:Gastric Juice / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000737:chemistry / Q000382:microbiology; D005782:Gels; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D008894:Milk Proteins; D010368:Pectins; D016062:Porosity; D019936:Probiotics; D013997:Time Factors; D000067816:Whey Proteins
chemical_list: D000464:Alginates; D001647:Bile Acids and Salts; D005782:Gels; D006603:Hexuronic Acids; D008894:Milk Proteins; D000067816:Whey Proteins; D010368:Pectins; D020723:Glucuronic Acid