| Summary: | 碩士 === 國立臺灣大學 === 食品科技研究所 === 90 === Bifidobacteria is regarded as one of the important probiotics. In this study, Bifidobacterium infantis CCRC 14633 and B. longum B6 were first encapsulated in alginate beads and oil-alginate beads. Susceptibility of these encapsulated bifidobacteria to simulated gastric fluid and viability of the encapsulated bifidobacteria during storage were examined.
It was noted that the encapsulation efficiency of both test organisms in alginate or oil-alginate beads was about 100 %. Encapsulation increased the survival of B. infantis CCRC 14633 and B. longum B6 in simulated gastric fluid (pH 2.0). The protection effect of oil-alginate beads toward B. longum B6 was better than that of alginate beads. The storage stability test with B. infantis CCRC 14633 revealed that encapsulation increase the survival of test organisms in orange juice, but not in diluted fermented milk. Encapsulated B. infantis CCRC 14633 showed less survival than free cells in distilled water and in 0.1 M CaCl2. While, cells encapsulated in oil-alginate beads exhibited a higher survival rate than those encapsulated in alginate beads. Besides, these encapsulated cells survived better in distilled water than in 0.1 M CaCl2. Rehydration of the freezed-dried beads containing B. infantis CCRC 14633 with citrate buffer (pH 5.5) resulted in a higher viable count of test organisms than those with phosphate buffer (pH 7.0). In addition, viability of the cells encapsulated in oil-alginate was higher than those encapsulated in alginate after rehydration. Although freeze-drying decreased the resistance of the encapsulated bifidobacteria to simulated gastric fluid, the protective effect of encapsulation on test organisms against this stress still existed when compared to free cells. Survival of the dried encapsulated bifidobacteria decreased as the storage temperature increased. Besides, bifidobacteria encapsulated in alginate was more stable than those encapsulated in oil-alginate during storage, which was more obvious at higher temperature.
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