Abstract:

Bifidobacterium longum subsp. longum BBMN68 is a new strain isolated from the feces of a centenarian living
in an area of Bama, Guangxi, China, known for the longevity of its residents. BBMN68 has general health benefits of
Bifidobacterium, but it is sensitive to oxygen and low pH. In order to resolve the shortcomings, microcapsules were prepared
by using sodium alginate, whey protein and vitamin E as wall materials, an extrusion method was used to protect BBMN68
cells in the nitrogen environment, and freeze-dried microcapsules were produced simultaneously. The results showed that
the wet microcapsules prepared under the conditions of sodium alginate 2%, whey protein 3%, vitamin E 10% (wt%) could
maintain the viable cells of 106 CFU/g after 21 d storage in yogurt, and the viable cells were up to 3.16×107 CFU/g after 2 h
in stimulated gastric fluid. The wet microcapsules were disintegrated completely in stimulated intestinal fluid. The freeze-dried
microcapsules prepared under the conditions of sodium alginate 2% and whey protein 3% in the nitrogen environment were stable for up
to 75 days at room temperature through isothermal accelerated test. Therefore, the microencapsulation technology can resolve well the
above-mentioned shortcomings of BBMN68, while providing a new and effective form for supplementing probiotics.

Key words: Bifidobacterium longum BBMN68, double emulsification, microcapsules, vacuum freeze-drying, stimulated gastrointestinal experiment