Method of preservation and type of protective agent strongly influence probiotic properties of Lactococcus lactis: A complete process of probiotic preparation manufacture and use

In order to assess the essential probiotic properties of a strain dedicated for administration in humans and animals, characteristics of finally formulated products, rather than the cells solely, seems to be of crucial importance. In this study, composition of protective blends for manufacture of L. lactis probiotic powders was optimized using a statistical experimental design. The powders, generated by either spray- or freeze-drying techniques, were subsequently subjected to storage testing, and in vitro digestion in simulated stomach and small intestine. Finally, maintenance of adherence capability to human enterocyte-like cell lines, was evaluated. Our data demonstrated that 10% trehalose ensures the highest viability of L. lactis bacteria upon both drying techniques (viability of 60-68%). Moreover, skimmed milk-protected spray-dried cells exhibit the highest resistance to harsh environmental conditions of stomach (53.9 ± 7.6% survival rate) and higher adhesion ability to HT-29 cell line after digestion (528 ± 29 cells per 100 epithelial cells).