title: Role of calcium alginate and mannitol in protecting Bifidobacterium.
abstract: Fourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins of Bifidobacterium animalis subsp. lactis Bb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (a(w)) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl(2) solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The a(w) of freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without a(w) adjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low a(w)s. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low a(w)s. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C).
authors: School of Biomedical and Health Sciences, Victoria University, Melbourne, Victoria, Australia.
authors: Dianawati
authors: D
authors: Dianawati
authors: Vijay
authors: V
authors: Mishra
authors: Nagendra P
authors: NP
authors: Shah
mesh_terms: D000464:Alginates / Q000378:metabolism*; D001644:Bifidobacterium / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D005615:Freezing; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D008353:Mannitol / Q000378:metabolism*; D050296:Microbial Viability / Q000187:drug effects*; D011309:Preservation, Biological / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D008353:Mannitol; D020723:Glucuronic Acid