In vitro survival of Bifidobacterium bifidum microencapsulated in zein-coated alginate hydrogel microbeads

The Bifidobacterium bifidum susceptibility in gastrointestinal conditions and storage stability limit its use as potential probiotics. The current study was design to encapsulate B. bifidum using sodium alginate (SA, 1.4% w/v) and different concentration of zein as coating material, that is, Z₁ (1% w/v), Z₂ (3% w/v), Z₃ (5% w/v), Z₄ (7% w/v), Z₅ (9% w/v). The resultant microbeads were further investigated for encapsulation efficiency, survival in gastrointestinal conditions, release profile in intestinal fluid, storage stability and morphological characteristics. The highest encapsulation efficiency (94.56%) and viable count (>10⁷ log CFU/g) was observed in Z₄ (7% w/v). Viable cell count of B. bifidum was >10⁶ log CFU/g in all the zein-coated microbeads as compare to free cells (10³ log CFU/g) and SA (10⁵ log CFU/g) at 4 °C after 32 days of storage. Therefore, B. bifidum encapsulated in zein-coated alginate microbeads present improved survival during gastric transit and storage.