Screening of Breast Milk-derived Bifidobacteria with Anti-inflammatory Activity and Preparation of Freeze-dried Microcapsules Thereof

In this paper, 21 strains of Bifidobacteria were isolated and identified from healthy breast milk samples, and the strain with the best activity was selected by spleen lymphocyte proliferation assay, drug sensitivity, haemolysis, bacteriostatic activity, and adhesion capacity evaluation. After identification by 16S rRNA, the lyophilisation technique was optimised and lyophilised microcapsules were prepared. The results showed that the bacterium was Bifidobacterium animalis subsp. lactis, named BA-9. B. lactis BA-9 was safe, with a hydrophobicity of 36.24%, a self-agglutination rate of 77.4%, and could significantly reduce NO activity in RAW264.7 cells, with in vitro Anti-inflammatory potential. Sodium alginate and carrageenan were prepared as a 1:1 composite wall with the addition of a composite lyoprotectant (11.25% skimmed milk powder, 4.93% xylooligosaccharides and 2.74% glycerol). The activity of B. lactis BA-9 microcapsules with the addition of lyophilisation protectant after lyophilisation decreased by only 1.3 lg CFU/g after simulated gastrointestinal fluid digestion. The survival rate of B. lactis BA-9 microcapsules could reach up to 90.03% for 28 days of storage at 4 ℃, which effectively enhanced the stability of storage. This study provides a research basis for the screening of Bifidobacterium bifidum with immuno-anti-inflammatory regulatory activities and the development and application of its lyophilised carrier.