Effects of inner-phase components of water-in-oil-in-water emulsion on low-pH tolerance of Lactobacillus acidophilus incorporated into inner-water phase

The incorporation of Lactobacillus acidophilus, which has a low acid tolerance, into the inner-water phase of water-in-oil-in-water (W/O/W) emulsion improved the bacterial survival rate in a model gastric juice. The components that enhanced the acid tolerance of the bacterium in W/O/W emulsion were investigated. Although the acid tolerance enhancement induced by the tested components was low at pH 2, some components significantly improved the tolerance at pH 4. In particular, the acid tolerance enhancement induced by yeast extract and sodium caseinate was marked.