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Viability of Lactobacillus plantarum encapsulated with poly-γ-glutamic acid produced by Bacillus sp. SJ-10 during freeze-drying and in an in vitro gastrointestinal model

Jang, Won Je, Choi, Sun-Young, Lee, Jong Min, Lee, Ga Hye, Hasan, Md Tawheed, Kong, In-Soo
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.112 pp. 108222
Bacillus (bacteria), Lactobacillus plantarum, adhesion, bacteria, bile salts, encapsulation, freeze drying, gastric juice, human cell lines, intestines, models, pH, polyglutamic acid, probiotics, survival rate, viability
In the present study, the probiotic Lactobacillus plantarum was encapsulated with 0.1%, 0.25%, or 0.5% 400-kDa poly-γ-glutamic acid (γ-PGA400) produced by Bacillus sp. SJ-10. The viability of the encapsulated cells was assessed under various stress conditions that are common to the processing and ingestion of probiotics, such as freeze-drying, exposure to simulated gastric juice (SGJ), and exposure to bile salt. During freeze-drying to make powder, L. plantarum levels decreased by 1.50 log colony forming units (CFU)/ml without encapsulation. When encapsulated with 0.5% γ-PGA400 under the same conditions, L. plantarum levels decreased by 0.19 log CFU/ml. In the SGJ condition (pH 2), all L. plantarum bacteria died within 1 h without encapsulation but exhibited the highest viability (decrease of 0.30 log CFU/ml) when encapsulated with 0.5% γ-PGA400. All groups had a high survival rate in the bile salt condition (pH 5.9). In the intestinal adhesion test with Caco-2 cells, the highest rate of adherence was 35.9% when the cells were encapsulated with 0.25% γ-PGA400. The present findings suggest that γ-PGA400 as an encapsulating material increases the viability of L. plantarum under various stress conditions.