Abstract

The aim of this study was to compare approaches commonly recommended in the literature for the improvement of the survival of probiotics in the human digestive tract. The survival of two probiotics, L. casei W56 and B. lactis W52, in the presence or absence of prebiotics, maize starch, fermented milk and upon encapsulation in calcium alginate-chitosan were evaluated. While B. lactis W52 was resistant to stomach juice, but sensitive to duodenal juice, L. casei W56 showed an exactly opposite behaviour. Overall the digestive survivability of probiotics was not improved by prebiotics, maize starch or encapsulation. A significant improvement of the overall survivability of B. lactis W52 (but not L. casei W56) during in vitro digestion was noted in milk and fermented milk, possibly due to reduction of the activity of bile against this probiotic. Overall no one method could be recommended universally for the improvement of probiotic survivability. Nevertheless, this research indicated that certain probiotic characteristics, such as susceptibility to bile or acid or ability to utilise matrix components as an energy source could perhaps be used in further research to select the most effective approaches to deliver viable cells into lower parts of the digestive tract.